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Eyyyy!
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Friday, June 26, 2026
June 2026 science summary
Wednesday, April 1, 2026
April 2026 science summary
Hello there,
This month I've got two articles about moisture cycling and water security, and one on predicted climate change and wildfire intensity in the Pantanal.
If you know someone who wants to sign up to receive these summaries, they can do so at http://subscribe.sciencejon.com (no need to email me unless the link breaks again).
GLOBAL WATER SECURITY:
Posada-Marín et al. 2024 is an interesting take on water security, arguing that since 40% of originates on land (upwind, potentially out of the hydrologic basin), accounting for that reveals more vulnerabilities (Fig 3) and risks to water security (Fig 5). Some of the results in Fig 5 don't look right to me, like the Paraná seems to have the same hazard for upstream vs. upwind approach, the vulnerability goes down from an upwind perspective (to middle), but Fig 5 says its risk is very high and unchanged. But despite that, the core idea is important: without accounting for where precipitation comes from, water security cannot be assured.
PANTANAL:
In a local example of what the paper above found, Bergier et al. 2018 shows that because much of the rain that falls in the Pantanal originates via trees transpiring moisture in the Amazon, continued Amazonian deforestation could lead to a 30% decrease in rain by 2100 (relative to 1961-1990, Table 2). Their estimate of reduced "precipitable water" of 25% was a hand-wave though: they arbitrarily picked a number that was more conservative than Boers et al. 2017 (which found losing 30-50% of the forest would decrease rain in the remaining forest by 40%). In better news, they found a 3C temperature increase would only drop rainfall by 1%.
Under the most likely SSP2-4.5 climate change scenario, Neto et al. 2026 predict that extreme heat days (where daily max temp >the 90th percentile) in the Pantanal will increase from an average of 36.5 days over the last 30 years to 85.8 from 2030-2060 (a 135% increase ). And days experiencing heatwaves (six or more consecutive days of extreme heat) will increase from the recent average of 8.8 to 50.7 under SSP2-4.5 (a rise from ~1 heatwave per year to ~5-6). This in turn is likely to drive increased wildfire intensity. Fig. 9 shows the spatial pattern of warming by season (a=summer, b=fall, c=winter, and d= spring when the biggest increase is seen).
REFERENCES:
Bergier, I., Assine, M. L., McGlue, M. M., Alho, C. J. R., Silva, A., Guerreiro, R. L., & Carvalho, J. C. (2018). Amazon rainforest modulation of water security in the Pantanal wetland. Science of The Total Environment, 619–620, 1116–1125. https://doi.org/10.1016/j.scitotenv.2017.11.163
Neto, J. B. F., Shen, S., de Cássia Ramos, R., & Pereira, G. (2026). Towards a new climate regime: heatwaves proliferate and reshape seasonality in the world’s largest tropical wetland. Bulletin of Atmospheric Science and Technology, 7(1), 5. https://doi.org/10.1007/s42865-026-00122-8
Posada-Marín, J., Salazar, J., Rulli, M. C., Wang-Erlandsson, L., & Jaramillo, F. (2024). Upwind moisture supply increases risk to water security. Nature Water. https://doi.org/10.1038/s44221-024-00291-w
Sincerely,
Jon
P.s. If you look closely at the image above, you can see a big alligator chilling on the riverbank behind me. She was unconcerned by our kayaks though.
Monday, December 1, 2025
December 2025 Science Summary
Greetings,
This month I am summarizing three science papers about climate change plus I wanted to share a cool idea I recently learned about.
Here's the cool idea: recent research in Colorado (by Julia Kintsch from ECO-resolutions among others) has found that simply adding lines of woody debris underneath underpasses (see the photo above) boosted underpass use by small mammals. Cover features composed of salvaged logs and branches with sufficient interstitial space through which small animals can move doubled the number of species documented using large bridges under an interstate to access habitats on either side. They detected 17 species using the cover features, including small mammals, amphibians, reptiles, and the federally threatened Preble’s meadow jumping mouse. This is a really cheap intervention worth trying out more broadly, please help spread the word!
If you know someone who wants to sign up to receive these summaries, they can do so at http://subscribe.sciencejon.com (no need to email me).
FORESTATION (REFORESTATION AND AFFORESTATION):
Wang et al. 2025 finds that earlier estimates of how much of the worth could be forested were much too high. One the one hand - this means we can't count on trees to do as much sequestering as some models hoped for. But as one of the authors (Susan Cook-Patton) points out (in this excellent post) the larger area wasn't feasible anyway, so this smaller estimate gives us more actionable priorities for planting. She also notes that while reducing fossil fuels (and protection of acutely threatened forests) is higher priority than forestation, we absolutely need all of the above. Note: reforestation is restoring trees where they used to be, afforestation is planting trees in what used to be grasslands or other ecosystems, forestation is both.
CLIMATE CHANGE - CARBON MARKETS AND ALBEDO:
Riley et al. 2025 have an update on an issue I've written about several times: that the albedo of trees (how much they reflect sunlight compared to bare soil) can reduce or even fully negate the climate benefit of trees in some cases. They looked at 172 tree planting projects in the voluntary carbon market to see how carbon credits issued compared to true climate impact once albedo was considered. On average 18% of the issued credits shouldn't have been, and 25% of the projects offered more than double the credits they should have once albedo was considered. 12% of the projects (a subset of that 25%) were even net harmful (representing 30% of total credits issued). In good news, 9% of projects actually had more benefit than estimated, and over half of projects had 0-25% of their issued carbon credits negated by albedo. This is important to get right, but a shortcut is to focus protection and forestation in more tropical places while avoiding areas with heavy snow cover and/or very light-colored soils (the pink places in Fig 2a are good to avoid).
DEFORESTATION AND CLIMATE CHANGE:
Franco et al. 2025 looks at how both deforestation and climate change have affected temperature and precipitation in the Amazon. Losing trees not only increases atmospheric carbon which drives global warming, for tropical forests in particular it also increases LOCAL warming and especially decreases water cycling. They found that deforestation caused 3/4 of the decline in dry season precipitation but only 17% of the increase in temperature. This is similar to other work which has found deforestation has delayed the onset of the rainy season in the Cerrado (Spera et al. 2016) and Pantanal (Lázaro et al. 2020).
REFERENCES:
Franco, M. A., Rizzo, L. V., Teixeira, M. J., Artaxo, P., Azevedo, T., Lelieveld, J., Nobre, C. A., Pöhlker, C., Pöschl, U., Shimbo, J., Xu, X., & Machado, L. A. T. (2025). How climate change and deforestation interact in the transformation of the Amazon rainforest. Nature Communications, 16(1), 7944. https://doi.org/10.1038/s41467-025-63156-0
Lázaro, W. L., & Oliveira-júnior, E. S. (2020). Thematic Section : Opinions about Aquatic Ecology in a Changing World Climate change reflected in one of the largest wetlands in the world : an overview of the Northern Pantanal water regime. Acta Limnologica Brasiliensia, 32, 8.
Riley, L. M., Cook-Patton, S. C., Albert, L. P., Still, C. J., Williams, C. A., & Bukoski, J. J. (2025). Accounting for albedo in carbon market protocols. Nature Communications, 16(1), 8810. https://doi.org/10.1038/s41467-025-64317-x
Spera, S. A., Galford, G. L., Coe, M. T., Macedo, M. N., & Mustard, J. F. (2016). Land-use change affects water recycling in Brazil’s last agricultural frontier. Global Change Biology, 22(10), 3405–3413. https://doi.org/10.1111/gcb.13298
Wang, Y., Zhu, Y., Cook-Patton, S. C., Sun, W., Zhang, W., Ciais, P., Li, T., Smith, P., Yuan, W., Zhu, X., Canadell, J. G., Deng, X., Xu, Y., Xu, H., Yue, C., & Qin, Z. (2025). Land availability and policy commitments limit global climate mitigation from forestation. Science, 389(6763), 931–934. https://doi.org/10.1126/science.adj6841
Sincerely,
Jon
Wednesday, October 1, 2025
October 2025 Science Summary
Greetings,
I've got a mixed bag of four mostly unrelated science articles this month.
If you know someone who wants to sign up to receive these summaries, they can do so at http://subscribe.sciencejon.com (no need to email me).
CLIMATE CHANGE:
Chen et al. 2025 reviews the evidence (from 21 studies with at least 10 years of data) that climate change may cause 3 problems (see Fig 1): mountaintop species going extinct when conditions become too warm for them, species not able to move upslope as fast as conditions change, and bottomland diversity declining b/c no warm-tolerant species can replace areas abandoned by species moving upslope. Using a model they found that mountaintop extinctions are not happening more than expected w/o climate change, many species ARE moving upslope but rarely having range contract, and only limited homogenization of bottomland species. They note including moisture changes and nitrogen deposition could have changed the results, and more research is needed to figure out why these problems are occurring in limited cases.
FOREST CARBON:
Schnabel et al 2025 has experimental evidence that after 16 years, planted forests in Panama with a mix of 5 native species sequestered 57% more aboveground carbon than monocultures. Both treatments lost soil carbon relative to the pasture they started with (see section 4.3 for possible explanations) but still gained a net of 24.7 t C / ha (90.7 t CO2e/ha) due to the aboveground gains. See https://news.mongabay.com/2025/04/diverse-forests-and-forest-rewilding-offer-resilience-against-climate-change/ for more.
DATA AND DEFORESTATION:
Roquette et al. 2025 is ostensibly about the technical details around land use mapping in Mato Grosso, Brazil. But it actually makes a much broader point: boring things like data sources and algorithms used can have an outsize backdoor policy impact. They argue that a shift in how land use was classified could sneakily allow a ton of deforestation. Basically by changing how "forest" is defined and reclassifying some forest as a type of savanna (confusingly, cerrado is an ecosystem but the Cerrado is a biome / region), this could allow deforestation since 80% of forest has to be set aside from development but only 35% of savanna does. In some cases the new map actually does the reverse (classifying what was savanna as forest) but that can be reversed upon request. The worst case scenario is that up to 4,1 million ha could be authorized for deforestation.
MINING AND TOXICITY:
Foerster et al. 2025 found that giant otters in the Pantanal are showing evidence of mercury contamination in the Pantanal – higher when they’re closer to gold mines (except for streams close to the mine over land but not connected by water). Their results aren’t conclusive but it seems likely that the values are high enough to be causing toxicity, and that otters aren’t able to flush out the mercury by molting their fur, nor by having selenium bind to the mercury. They measured mercury in fur rather than directly in the liver, but based on other research they think it’s likely levels are high enough in some animals to cause serious toxicity and perhaps even death.
REFERENCES:
Chen, Y.-H., Lenoir, J., & Chen, I.-C. (2025). Limited evidence for range shift–driven extinction in mountain biota. Science, 388(6748), 741–747. https://doi.org/10.1126/science.adq9512
Foerster, N., Soresini, G., Leuchtenberger, C., Bócoli, D. de A., Paiva, J. de B., Brait, C. H. H., & Mourão, G. (2025). Pervasive mercury contamination of a semi-aquatic apex predator across the Pantanal wetland. Environmental Conservation, 1–6. https://doi.org/10.1017/S0376892925100155
Roquette, J. G., Vacchiano, M. C., Daher, F. R. G., & Finger, Z. (2025). Pseudo-legal deforestation due to changes in the classification of native vegetation in Mato Grosso, Brazil. Environmental Conservation, 1–7. https://doi.org/10.1017/S037689292510012X
Schnabel, F., Guillemot, J., Barry, K. E., Brunn, M., Cesarz, S., Eisenhauer, N., Gebauer, T., Guerrero‐Ramirez, N. R., Handa, I. T., Madsen, C., Mancilla, Lady, Monteza, J., Moore, T., Oelmann, Y., Scherer‐Lorenzen, M., Schwendenmann, L., Wagner, A., Wirth, C., & Potvin, C. (2025). Tree Diversity Increases Carbon Stocks and Fluxes Above—But Not Belowground in a Tropical Forest Experiment. Global Change Biology, 31(2). https://doi.org/10.1111/gcb.70089
Sincerely,
Jon
p.s. These four foster puppies were getting some wiggles out in my yard before a "puppy party" which raises money for an animal rescue (Homeward Trails) and helps them find homes
Thursday, May 1, 2025
May 2025 science summary
Merry May,
This month I've got four articles on freshwater, plus one on whether climate mitigation can be harmful to wildlife if done wrong (spoiler: yup).
If you know someone who wants to sign up to receive these summaries, they can do so at http://bit.ly/sciencejon (no need to email me).
FRESHWATER:
Petry et al. 2025 has predictions of changing streamflow and flooding across South America by 2100 under a moderate climate change scenario. Figure 4 has the key findings about how much more or less frequent floods may be. Note that “RP” means “return period” as in a “5 year flood” or “100 year flood” (the magnitude of flooding you’d expect on that frequency / rarity, so higher numbers mean more severe flooding). RPCF means how much more or less frequent those floods would be (with negative sign indicating less frequent flooding, e.g. the -2 on the Paraguay river in the Pantanal means half as often). But much more flooding is expected in Peru, Ecuador, Colombia, and Southern Brazil, and parts of the Amazon will see 1/10 as much flooding as they historically have. They find Pantanal floods (in the Paraguay River and some tributaries like Cuiaba and Negro) will be roughly half as frequent and half as severe, they don’t have a clear trend in the Chaco, and in Chile the area from roughly Santiago to Valdivia has some rivers where flooding will be ~2-3 times less frequent while the northern part of Chile will only see slightly less flooding.
Lehner et al. 2024 is a summary of a new "Global Dam Watch (GDW)" open dataset of 41,000 river barriers and 35,000 reservoirs (see Fig 1 for a map). While national and regional datasets are more complete (e.g., NID has 90k points in the US, AMBER has 630k in Europe), this is the most comprehensive free global dataset (see Table 2) and it includes estimated reservoir volumes mostly for reservoirs >10 km2.
Cho et al. 2023 did a ton of modeling (Fig 7) to estimate how conservation (mostly reforestation along streams) could have affected the water supply of São Paulo. They found the increased habitat could serve as an "invisible reservoir" for water in soil, and in a highly idealized scenario (lots of new forest in all the right places among others) streamflow could be boosted by 33% (and drought costs reduced by 28%). They don't report numeric results for their less ideal scenarios, and all scenarios exclude the water consumption of growing trees. In a conversation with one of the study's authors, they mentioned that it likely took about 30 years (I think) for the "water savings" of nature (fog capture plus slowing down runoff during high rain events) to outweigh the water consumption of growing trees. In other words, in this case in the short term adding trees could result in lower streamflow even though in the long run it would increase streamflow. Understanding the timeline and tradeoffs is key so people who live there know what to expect. From chatting w/ other hydrologists about this, it's clear that results like this vary a lot depending on things like soil type, weather and climate, type of forest, and much more. There's an article about this one at https://www.nature.org/en-us/about-us/where-we-work/latin-america/brazil/stories-in-brazil/invisible-reservoir/
Pompeu 2025 quantitatively models how different drivers have impacted total water surface area (as a decent proxy for total flow / water quantity) in the Pantanal. The paper found the biggest driver of water level was 1) the presence or absence of having natural vegetation at least 50m around springs, followed by 2) natural veg riparian buffers along rivers (buffer width increasing w/ river width as per the Forest Code), followed by 3) replacing conventional monoculture ag w/ something w/ deeper root systems (agroforestry, permaculture, full restoration if feasible, etc.), followed by 4) preventing more dams.
CLIMATE MITIGATION AND WILDLIFE:
Smith et al. 2025 asks what the net impact of climate mitigation on land (including bioenergy crops, reforestation, and afforestation) is on the total habitat area for 14,000 vertebrate species. Fig 1 summarizes the idea well - climate change can reduce suitable habitat, but climate mitigation can also either add or remove habitat directly. Fig 4 has their global recommendations - basically leave most ecosystems alone, reforest several areas (SE Asia, Eastern US, Mexico, and much of Europe) and in a few tiny places grow bioenergy crops. In other words, typically planting trees on grasslands or other habitat types destroys more habitat than it saves through climate mitigation. But planting trees in cleared forests is a win-win.
REFERENCES:
Cho, S. J., Klemz, C., Barreto, S., Raepple, J., Bracale, H., Acosta, E. A., Rogéliz-Prada, C. A., & Ciasca, B. S. (2023). Collaborative Watershed Modeling as Stakeholder Engagement Tool for Science-Based Water Policy Assessment in São Paulo, Brazil. Water, 15(3), 401. https://doi.org/10.3390/w15030401
Lehner, B., Beames, P., Mulligan, M., Zarfl, C., De Felice, L., van Soesbergen, A., Thieme, M., Garcia de Leaniz, C., Anand, M., Belletti, B., Brauman, K. A., Januchowski-Hartley, S. R., Lyon, K., Mandle, L., Mazany-Wright, N., Messager, M. L., Pavelsky, T., Pekel, J.-F., Wang, J., … Higgins, J. (2024). The Global Dam Watch database of river barrier and reservoir information for large-scale applications. Scientific Data, 11(1), 1069. https://doi.org/10.1038/s41597-024-03752-9
Petry, I., Miranda, P. T., Paiva, R. C. D., Collischonn, W., Fan, F. M., Fagundes, H. O., Araujo, A. A., & Souza, S. (2025). Changes in Flood Magnitude and Frequency Projected for Vulnerable Regions and Major Wetlands of South America. Geophysical Research Letters, 52(5). https://doi.org/10.1029/2024GL112436
Pompeu, J. (2025). Cross-Boundary Drivers of Water Cover Reduction in the Pantanal Wetland and Implications for its Conservation. Wetlands, 45(3), 32. https://doi.org/10.1007/s13157-025-01916-w
Smith, J. R., Beaury, E. M., Cook-Patton, S. C., & Levine, J. M. (2025). Variable impacts of land-based climate mitigation on habitat area for vertebrate diversity. Science, 387(6732), 420–425. https://doi.org/10.1126/science.adm9485
Sincerely,
Jon
p.s. This is a sea lion lazing about in Valdivia who happened to yawn as I was watching them.
Monday, February 3, 2025
February 2025 science summary
Good day,
I have a mixture of papers as usual this week, covering using AI to do lit review (on natural climate solutions), more on seaweed to reduce cattle emissions, one on fire management, and one bad study on return-to-office mandates.
Also, I have no idea how the cost and complexity of this new AI monitoring tool (SPARROW, https://blogs.microsoft.com/on-the-issues/2024/12/18/announcing-sparrow-a-breakthrough-ai-tool-to-measure-and-protect-earths-biodiversity-in-the-most-remote-places/) compares to simpler camera trap setups but I’m especially curious if the acoustic component might be able to detect amphibians or birds unlikely to be visible in a camera trap (thanks to Tara Schnaible for passing this on). If any of you are using camera traps and/or microphones for biomonitoring I'd love to hear your thoughts!
If you know someone who wants to sign up to receive these summaries, they can do so at http://bit.ly/sciencejon (no need to email me).
CLIMATE CHANGE AND AI METHODS:
Chang et al., 2024 uses specialized large language models to assess evidence for 11 co-impacts (positive or negative) of natural climate solutions (NCS). They extracted data from 257,266 studies (after screening 2.3 million)! Most (87%) focused on management, ~30% covered protection and/or restoration, but <2% mentioned cost or equity or Indigenous peoples or local communities. Fig 2 has a nice breakdown of NCS pathways, biome, co-impacts, etc., and Fig 4b maps countries by both evidence and mitigation potential. Paraguay and Republic of the Congo pop as highest carbon w/ lowest evidence (needing research), while the Americas and E/SE Asia have high evidence and high carbon (needing implementation). Fig 3 shows the volume of evidence for how 22 NCS pathways intersect with the 11 co-impacts (9 of which relate to human well-being). They argue that West and Central Africa deserves special research attention as evidence and human development index are relatively low while NCS potential and threatened species are high. One key caveat: evidence volume does not mean evidence quality. For example, there are many papers on sowing legumes in pasture to reduce enteric methane, but I'm not aware of any that are both accurate and precise enough for implementation (since putting them in the wrong places would lead to increased emissions). But this is still a great example of using AI to review a much larger body of evidence than would be possible manually.
CATTLE AND CLIMATE CHANGE:
Meo-Filho et al. 2024 is an important study (part of a special issue of papers around the sustainability of animal foods and plant alternatives, https://www.pnas.org/topic/561). There's been lots of research with hyperbolic claims about red algae reducing methane production in cattle (mostly in vitro, or tests in a petri dish). I believe this is the first paper to measure methane reductions not only 1) in vivo (a test of what happens in real animals) but 2) in the grazing phase of their life cycle. Most American cattle graze for very roughly 15 months before spending 3 months in a feedlot, and they emit more methane per day when grazing. Only 15% of total cattle production GHGs come from the feedlot phase, so even big reductions then can't touch cattle's high carbon footprint. But this paper found supplementing with the seaweed reduced GHGs relative to control animals by 38% over 90 days with no side effects! That is great news and this is work worth following up, BUT a few key caveats: 1) this was a study of only 24 animals, 2) the animals began at 15 months when they would typically go to a feedlot, to show how much this could really reduce the total carbon footprint of cattle (and if any side effects crop up eventually) it would need to be tested on calves from when they are weaned off of milk to when they go to slaughter, and 3) variations in cattle breed, the dominant type of grass they're eating, and climate could all affect the results. So it's very good news, but does not yet mean it's possible to produce a burger w/ 1/3 less carbon. Also, while the numbers are hotly contested, remember that the carbon footprint of beef is very roughly 10* that of pork or chicken (~50* the GHG of beans), so even if the reduction IS scalable, beef will still be a high carbon food.
Cowley et al. 2024 is a paper with very exiting results about reducing the carbon footprint of beef. They fed Australian Angus cows in a feedlot red seaweed (Asparagopsis) infused into vegetable oil, and added it to their diet at three concentrations of CHBr3 from the sewaweed, plus a control w/ no seaweed (5 cows for each of the four treatments). The medium and high doses reduced enteric methane (CH4) by 98% and 99%, with no significant reported side effects. Other studies have seen less impressive reductions in live cattle (e.g. George et al. 2024 found ~50% reduction), although in petri dishes 99% reductions have been achieved before. The discussion covers potential factors influencing the CH4 reduction, including dose, how much of the feedlot diet is grain vs grass, and cattle breed. Caveat - one high dose cow (20% of the sample) got acidosis and had to be removed, all groups had some health problems, and the medium and high doses did increase neutrophil and platelet count. Overall - at medium and high doses the methane was almost eliminated without affecting meat taste or safety, and without clear cattle health impacts. So the study is very promising, but needs to be replicated with larger groups and different contexts (including eventually a study using Asparagopsis during both the entire grazing phase and feedlot phase).
FIRE MANAGEMENT:
Lacey et al. 2024 highlights opportunities for prescribed fire and/or thinning (removing trees and/or brush) to proactively reduce risk for vulnerable communities and areas of high ecological value. Socially vulnerable communities are less likely to get this preventive fire management, but the authors find there are "win-win" opportunities for places high in: ecological value (specifically biodiversity, connectivity, and climate resilience), ecosystem services (carbon and drinking water), social vulnerability (see Table 1 for indicators), and the potential for wildfire mitigation to be effective (the last is based on fire hazard and vegetative cover). Fig 2c has their top priority areas, including big chunks in the Appalachians, Ozarks, and Rocky Mountains (esp. CO and ID), and Fig 4 shows in yellow where those overlap with the USFS top 10 firesheds. Fig 3 shows how much better their priority areas perform against several indicators than a focus solely in fire mitigation potential; as you'd expect optimizing for social vulnerability, ecosystem services, and ecological value results in sites that score a lot better on those indicators! That may seem obvious, but to reframe: in conservation we OFTEN don't include certain objectives in our planning but still expect to have great stories about all the co-benefits we got anyway. This paper is a great pitch for the value of inclusion; planning for what you care about up front will help you focus work on the places where you can have the most impact.
RETURN TO OFFICE MANDATES:
I already put this on LinkedIn but also wanted to flag here that I thought the recent Ding & Ma 2024 study from University of Pittsburgh (which has had a lot of media attention w/o scrutiny) was misleading. They found that 1) return to office mandates don't improve employee or company performance and 2) these mandates are used more to blame employees and "grab power" than to try and improve performance. This doesn't appear to be peer-reviewed research, which makes me more skeptical by default (it could still be right, but there's no screen for bad methods or misleading results). The paper's tone and methods make it look like they set out to prove some preconceived notions rather than exploring what's going on with an open mind, and the way they assert attribution and causation to some findings they report appear unsupported by the data. Their interpretations of their data are plausible, but even if you trust the data there are other valid interpretations which are also plausible.
The reason I posted this despite it seeming like a "bad" study is to flag the role of bias in reading science. I believe that if I was required to go to the office more often, it would negatively impact my performance and happiness. I can point to personal experience backing that up (I'm more willing to work longer hours when I don't have a commute or when I'm getting hungry but don't have food nearby to keep working). But in situations like this where I have an opinion and feel inclined to "right on!" what I read, that's exactly when I need to slow down and read carefully since I know I have bias leading me to accept certain results and interpretations as convincing. Also - read a news article about science and wondering if it's misleading? I generally first look for the press release from the host institution (to read a summary that the authors would have had a chance to review to reduce accidental misunderstanding, although they are still unreliable whether on accident or on purpose to hype it: https://business.pitt.edu/return-to-office-mandates-dont-improve-employee-or-company-performance/ ), then read the actual paper.
Don't assume the press release, or even my summary is accurate! Always check before you share or act on a research summary.
REFERENCES:
Chang, C. H., Erbaugh, J. T., Fajardo, P., Lu, L., Molnár, I., Papp, D., Robinson, B. E., Austin, K. G., Castro, M., Cheng, S. H., Cook-Patton, S., Ellis, P. W., Garg, T., Hochard, J. P., Kroeger, T., McDonald, R. I., Poor, E. E., Smart, L. S., Tilman, A. R., … Masuda, Y. J. (2024). Global evidence of human well-being and biodiversity impacts of natural climate solutions. Nature Sustainability. https://doi.org/10.1038/s41893-024-01454-z
Cowley, F. C., Kinley, R. D., Mackenzie, S. L., Fortes, M. R. S., Palmieri, C., Simanungkalit, G., Almeida, A. K., & Roque, B. M. (2024). Bioactive metabolites of Asparagopsis stabilized in canola oil completely suppress methane emissions in beef cattle fed a feedlot diet. Journal of Animal Science, 102(April). https://doi.org/10.1093/jas/skae109
Ding, Y., & Ma, M. (Shuai). (2024). Return-to-Office Mandates. In S&P Global Market Intelligence. https://doi.org/10.2139/ssrn.4675401
Lacey, L. M., Suraci, J. P., Littlefield, C. E., Busse, B. S., & Dickson, B. G. (2024). Informing proactive wildfire management that benefits vulnerable communities and ecological values. People and Nature, August, 1–15. https://doi.org/10.1002/pan3.10733
Meo-Filho, P., Ramirez-Agudelo, J. F., & Kebreab, E. (2024). Mitigating methane emissions in grazing beef cattle with a seaweed-based feed additive: Implications for climate-smart agriculture. Proceedings of the National Academy of Sciences, 121(50), 2–9. https://doi.org/10.1073/pnas.2410863121
Sincerely,
Jon
p.s. the photo is of a salt marsh at The Wetlands Institute in Stone Harbor, NJ
Thursday, January 2, 2025
Best of 2024 science summaries
Happy New Year,
How better to celebrate the new year than with old science?!
As usual, here are my favorite 15 reruns (article summaries) from 2024, plus a few of my favorite bits about AI since I keep getting requests for more of that:
- Don’t put anything sensitive into AI! Enterprise licenses provide some protection for non-public but not highly sensitive info.
- I loved these tips for better AI prompts to help you get better results: https://www.oneusefulthing.org/p/getting-started-with-ai-good-enough
- This is a great overview of some really good and really bad use cases for AI: https://www.oneusefulthing.org/p/15-times-to-use-ai-and-5-not-to
- Remember that AI is always changing. As of mid-December, Google Gemini’s NotebookLM not only turns a PDF you upload into an NPR-style podcast, it also now lets you interact w/ the “hosts”!
Upset at the articles I missed? Please email me your own favorites from 2024 and I'll do what I can to include them in upcoming summaries.
As always people can sign up to receive these summaries at http://bit.ly/sciencejon (no need to email me). On with the reruns!
CLIMATE CHANGE
OK, for years people have been hyping the potential of a kind of seaweed (Asparagopsis) to reduce methane emissions in cattle. But the in vitro evidence was mixed - with potential toxicity and downsides a concern if the dose wasn't just right. George et al 2024 is a live trial with good news! They found methane emissions from cattle given an Asparagopsis additive were cut roughly in half compared to control, with 6.6% higher weight gain per unit of feed and no substantial impacts on quality or health (fat color maybe a bit better, tenderness maybe a bit worse). The methane reduction peaked at day 21 and declined afterwards, but since most cattle are in feedlots only ~3 months (ranging from 1.5-4) the decline after day 100 is pretty moot. That's a lot of potential! The only potential downsides were ~50% higher bromine residues in kidney and muscle (I couldn't quickly find guidance on safe levels). Caveats: 1) there were no conflicts declared but the authors appear to almost all work as feedlot consultants and it's single rather than double-blinded, 2) in the US the feedlot phase is only about 15% of the lifecycle emissions of a cow (and of that, some is from growing crops and nitrous oxide) so TOTAL impact on CO2e / kg beef is not as dramatic. Overall my take is 1) this should absolutely be tested and replicated more - anything that reduces the very high carbon of beef is worth pursuing. BUT 2) if this is marketed as "green beef" or license to avoid reductions, it could be net harmful for the climate. and 3) IF spraying this solution on grass worked similarly and didn't inhibit development of calves, the impact could be much higher (since ~80%ish of a cow's life is grazing prior to feedlot, and methane emissions are higher on grass than feed). So let's test that too (note: there’s a new study claiming a ~1/3 reduction in methane during grazing via seaweed supplements that I haven’t reviewed yet). There's a blog about this at https://www.theguardian.com/australia-news/article/2024/aug/18/feeding-seaweed-supplement-to-cattle-halved-methane-emissions-in-australian-feedlot-study-finds
Trencher et al, 2024 is an analysis of the quality of carbon credits on the voluntary market. They focus on the 20 companies retiring the most credits between 2020-2023 (134 million metric tons CO2e), which is 20% of all global retirements on the three registries (see Fig 1 for company list). They found 87% of credits have a high risk of not providing real additional reductions (6% were low risk, most of the rest was medium), and 97% of credits focused on avoiding emissions rather than removal. Note that they classified all REDD+ (reducing deforestation and/or degradation) as high risk given that they have often 1) overestimated additionality, 2) not stopped deforestation, and/or 3) displaced deforestation elsewhere (aka 'leakage'). They also classify large-scale renewable energy as high-risk, since the price of credits is not typically the decisive factor in those projects (they are often built w/ or w/o credits) and they are often build in countries w strong government support for renewable energy. They also found that companies strongly prefer the cheapest credits (which creates demand for lower-quality offsets) often from older projects, although some companies have paid a lot more for REDD projects. The authors call for more regulation of the voluntary market, and for companies not using voluntary credits to support claims of offsetting emissions.
CONSERVATION IMPACT:
Langhammer et al. 2024 is the big splashy new Science paper looking at the global impact of conservation. It's a meta-analysis of trials comparing interventions to counterfactuals (similar areas w/o action). They found conservation helps 2/3 of the time (45% of trials led to absolute improvement in biodiversity, 21% reduced biodiversity loss), but is harmful 1/3 of the time (in 21% of trials biodiversity declined more due to conservation, in 12% it improved less due to conservation), and only 2% of trials showed no difference). That's not a great track record - I'd hoped net harm would be rare (1/3 is very high!), and just over half the time we're losing biodiversity despite trying to stop it. Fig 2 helpfully shows how impact varies by type of intervention: protected areas show the smallest positive effect on average, and invasive species removal shows the largest positive effect. I'd ignore "sustainable use of species" b/c it's a weirdly broad category that somehow only included 4 papers on wildlife hunting and 1 on fishing, although a few fishing papers are included under protected areas (details in the supplement - this makes me think their sample is not representative of conservation broadly). While the authors conclude conservation is working and we should do more of it, I bet if this was a paper on medical efficacy we'd consider interventions that are 2/3 helpful and 1/3 harmful an urgent cry to improve efficacy BEFORE we try to scale work that is so often ineffective or harmful. Would you send your kids to a school where 1/3 of students learned less than kids not in school at all?
EVIDENCE ASSESSMENTS / SCIENTIFIC REPRODUCIBILITY:
Scientists often complain policy makers don't follow our recommendations (or even read them). But Brisco et al. 2023 finds that recommendations from meta-analyses tend to change over time as research continues. They looked at 79 papers (121 meta-analyses) and found that over time 93% of analyses either had a big change in effect size (+- 50% or more, see Fig 2 for examples) or change in statistical significance (see Fig 3). The key results are in Fig 5, which I find pretty confusing. Results staying consistently statistically significant w/ each study is rare, and ~25% of analyses showed a reversal in effect (from positive to negative or vice versa). Those reversals are the change we care the most about since it means action can backfire. BUT if you ignore the studies that were never statistically significant (seems safe) it's only 12% of analyses that flip, and if you also ignore the ones that lost significance (meaning the reversal is less meaningful) it goes down to 11%. That's still pretty bad though - 1 time out of 9 the scientific recommendation might lead to the opposite outcome we intend. They recommend scientists use cumulative meta-analyses to look for trends, and the reminder that we're often wrong reinforces the need for adaptive management and an empirical approach to seeing what works in a given context.
FIRE:
Pivello et al. 2021 is a good comprehensive overview of wildfire across Brazil. It's long and dense so hard to summarize! Natural fires are most common at the beginning of the wet season when lightning ignites accumulated dry vegetation. Fig 1 has an overview of fire by biome: the Amazon followed by Cerrado have the most fires; the Pantanal and Cerrado typically have the highest % burned (they are both fire-dependent, as is the Pampas, see Fig 2), and in 2020 the Pantanal had roughly triple the % burned and fire density as others. Pollen evidence (from a different study, Power et al. 2016) indicates fire activity in the Pantanal peaked about 12,000 years ago (people have only lived there for about 8,000 years, and grazed cattle for ~250). Introducing cattle has caused a shift from burning every 3-6 years (mostly in the beginning or sometimes end of the wet season) to burning every year or two during a relatively dry part of the wet season (see Fig 6). Conversely, fire suppression in the Cerrado has also driven woody encroachment of savannas. In the Amazon and Atlantic Forest, natural fire is rare and very infrequent, making fire especially harmful as species are not adapted to it. The combination of deforestation and drought make it much easier for fire to spread (and Amazonian deforestation means more drought in the Pantanal). 1/3 of the forest in the Amazon from 2003-2019 were associated w/ deforestation. Indigenous people mostly used fires in small areas, but since European colonization it's used at larger scales to clear land permanently (or alternately suppressed, see Fig 7 for a nice timeline of fire landmarks). Integrated fire management (IFM) is uncommon (except a few federal protected areas, mostly in the Cerrado). Only Minas Gerais and Roraima states have IFM laws. The authors recommend: 1) fire management policy should include climate mitigation and poverty reduction to reduce fire risk; 2) better fire monitoring and management systems; 3) filling knowledge gaps around drivers of fire, how fire impacts wetlands, human dimensions of fire, impacts of different fire regimes on grazing productivity and carbon; 4) better enforcement of illegal fire use (including more resources); 5) including local communities in developing fire management plans, and 6) national and state level fire policies with adequate resources for implementation (including data collection and sharing, and clear and simple rules about fire use).
Balch et al. 2024 found that over the last 20 years fires in the US have been spreading faster. In the Western US over 20 years the average peak daily growth rate (the average of the fastest each fire grew on a given day) increased 2.5 times (in California they increased by 4 times). The fastest 3% of fires nationally (spreading more than 1,620 ha in a day) destroyed between 78-89% of the buildings lost to fire (the paper lists each number in different section for the same stat). I’ve heard a lot more about severity and frequency and extent of fire, but thinking about speed is also important as faster fires are harder to respond do, and may make really smooth coordination increasingly important. Increases in drought conditions and potential increases in high winds could make this worse over time.
FRESHWATER:
Flitcroft et al. 2023 notes that counting effective freshwater protection globally is really hard (as is getting effective protection to happen). Fig 1 has a nice summary of how restrictive different protection mechanisms are. They also call for both better management of existing protected areas (PAs) to include freshwater conservation needs, and protections for freshwater in new places. While issues around data resolution and data availability continue to pose challenges to freshwater conservation, they argue that more explicit consideration of both freshwater and terrestrial objectives in any area-based protection is a good start.
Jasechko et al. 2024 is a global assessment of groundwater levels since 2000 (using 170,000 wells and 1,700 aquifers) and comparing them to earlier trends for ~1/3 of those aquifers. They found 36% of aquifers were drying up (water level dropping deeper by 0.1 m / yr or more), and 6% of aquifers were improving (water level rising 0.1 m / yr or more), w/ 58% of aquifers not changing quickly in this century. 30% of the aquifers where they had 40 years of data declined faster in the 21st century than the 20 years prior (see Fig 3), but in 49% of those aquifers declines slowed or reversed. Unsurprisingly the trend is worst in drylands w/ farmland, and groundwater deepening is globally correlated w/ low precipitation, high evapotranspiration, and extent of agriculture. See Fig 1 and 2 for global map of trends, highlighting hotspots of decline in CA, the US high plains, Iran, India, central Chile, and a few others. There's a news article about the study at https://www.cnn.com/2024/01/24/climate/groundwater-global-study-scn/index.html
Wang et al. 2024 looks at how climate change has changed the seasonality of river flow (how much it varies month to month, including frequency of droughts and floods). They found that ~14% of long-term river gauges show changes in seasonality over the last 50 years that isn't driven by changing annual precipitation. The surprise is that seasonality is mostly DECREASING counter to the narrative of more floods and droughts (see Fig 1 for a map of results, and Fig 2 which adds detail). In their figures brown means less seasonality (more even flow): "L+" means low flows become higher flows (NOT higher frequency of drought) while "H-" means floods see lower flood volume (again NOT lower frequency of flood events). You'll see most of North America, most of Europe, and some of Russia have seen reduced seasonality in recent decades. Blue means MORE seasonality, focused in: SE Brazil, some European countries, and in the US the SE and some of the Rocky Mountains. The explanation is worth reading in full, but in brief: 1) snow melting earlier means less runoff from snow at the same time as spring rains, 2) early spring greening means more water gets transpired, 3) it's more complicated in places not dominated by snowmelt.
HORIZON SCANNING / EMERGING ISSUES:
I realized I've only rarely reviewed Bill Sutherland's annual "horizon scan" article listing 15 emerging conservation issues that potentially deserve to be better-known. Last year (I just read the 2024 version a year late) they used artificial intelligence to generate some of the ideas but none made the cut. Here's the final list so you can decide if any are worth looking up (and here’s the brand new 2025 paper if you want to catch up):
1. New sources of hydrogen for energy (mining or electrolysis instead of natural gas),
2. Decarbonized ammonia (making fertilizer w/ lower carbon emissions but could increase fertilizer wasted),
3. Feeding people and/or animals w/ cultivated bacteria,
4. Light-free artificial photosynthesis (yes, it's as weird as it sounds) for indoor ag,
5. Enhanced rock weathering at scale (putting rock dust on croplands to sequester carbon),
6. Potential global declines in earthworm populations (more data is needed to see if UK decline is representative),
7. Ecoacoustics to monitor soil ecology (testing how meaningful soil sounds are for estimating things like biodiversity and water flow),
8. Wildfire affecting El Niño and La Niña phase (aerosols leading to the La Niña phase),
9. Benchtop DNA printers (potential to eventually allow guerilla genetic engineering),
10. Better predicting chemical toxicity from early data,
11. a skyscraper city planned in Saudi Arabia that birds could crash into when migrating from Europe to Africa.,
12. Sea urchin die-offs (possibly from disease) leading to algal overgrowth on corals and other marine ecosystems,
13. Ocean-based carbon removal (from the air or dissolved in water to stable forms),
14. Warming "twilight zones" (200-1000m below sea surface) affecting global nutrient and carbon cycles, and
15. Melting Antarctic ice changing deep sea currents.
MAMMALS:
Greenspoon et. al 2023 is an attempt to estimate the biomass of all wild mammals on earth (combined), arriving at 60 Mt total: 20 Mt (million metric tons) on land (half from "even-hoofed" mammals, see FIg 2), and 40 Mt in oceans (23 Mt of which comes from baleen whales). But the kicker is that they estimate human biomass at 390 Mt, and livestock biomass at 630 Mt (420 Mt from cattle: which is more than all humans plus all wild land mammals). Fig 4 awkwardly tries to compare all mammal biomass on earth, showing how wild species have been squeezed. The wild mammal estimates mostly come from the IUCN red list which skews towards expert assessments of more threatened spp., and the numbers won't be "right" for several reasons (these estimates are hard, and the data are highly limiting). But it seems solid that humans and livestock substantially outweigh wild mammals.
There's a good critique of the paper (arguing that Greenspoon et al. underestimate biomass by a factor of 5.5) by Santini et al. here https://www.pnas.org/doi/10.1073/pnas.2308958121 and a reply from the Greenspoon authors pointing out why the methods used in the critique are also (differently) flawed: https://www.pnas.org/doi/10.1073/pnas.2316314121
MIGRATORY SPECIES / WILDLIFE CONNECTIVITY:
The new State of the World's Migratory Species report (UNEP-WCMC 2024) has an update on how the 1,189 migratory species in CMS are doing. Almost half (44%) are in decline (with 22% at risk of extinction, including 97% of listed fish spp), 1/3 are stable, and the rest are split between improving and unknown. The report also notes that 399 spp not even listed in CMS (including ~200 fish spp, ~150 bird spp, and ) are at risk (from critically endangered to near threatened). See Fig 2.10b for an overview of which migratory species CMS leaves out (including horseshoe crabs!) and 2.10c for the subset at risk. Unsurprisingly the main threats are habitat loss (along w/ degradation and fragmentation) and overexploitation (hunting and fishing). Recommendations on page ix-xi are familiar and unsurprising (albeit important). There's a blog about this paper with key highlights at: https://www.unep.org/news-and-stories/press-release/landmark-un-report-worlds-migratory-species-animals-are-decline-and
Littlefield et al. 2024 (I'm a minor author) examines how wildlife road crossings can be beneficial to help species adapt to climate change. We recommend that when siting crossings we should consider a) current wildlife movements, AND expected short-term and long-term shifts in species range and migrations due to b) climate change AND c) human land use change (expansion of housing, ag, etc.). We show how doing this was accomplished for elk in Colorado.
For this to work well, diversion fencing is important to channel wildlife to crossings, and avoiding future fragmentation is key. The paper is open access. There's a press release for the paper here: https://fish.freeshell.org/publications/Littlefield2024-PressRelease.pdf
POLLINATORS:
Li et al. 2024 is a methods paper about using land cover data to predict floral resource availability for pollinators. I'm an author despite minimal input; the lead author based this on work by the last author, who I provided some guidance to when he was a postdoc. There are a few potentially interesting things in here. 1) Most pollinators don't make much honey, so their populations are limited by the time of year w/ the least food available (pollen and nectar). The methods here help you figure out those bottlenecks if you want to target habitat restoration to boost pollinator populations. 2) Plants vary a lot in how much nectar and pollen they make. Not every crop makes flowers that feed pollinators (likely obvious, but some crops and cover crops are harvested or terminated before flowering, and wind-pollinated plants don't have nectar). Trees produce a ton of nectar and pollen. 3) The paper looked at two different ways to map land cover, and surprisingly the simpler approach worked as well (similar error levels)! It's a good reminder to always question whether you need more complexity and accuracy. If you just have a garden and want more bees and other pollinators, this blog post I wrote may help: https://sciencejon.blogspot.com/2024/05/new-paper-on-mapping-pollinator.html
WETLANDS:
The latest report on the status of wetlands in the US (excluding AK and HI) is a bummer but has some useful info. Key summaries are in Fig 9 and Table 2, but in short on net 221,000 acres of wetlands were converted, mostly to ag and tree plantations followed by housing developments. But that net change hides that fact that we actually lost 670,000 acres of vegetated wetlands, with non-vegetated wetlands like ponds, sandbars, and mudflats increasing (but NOT providing nearly as much ecological value). The report calls for more coordination to achieve no net loss of wetlands, to update and improve the National Wetlands Inventory, develop and implement better wetland conservation and management (duh), and commit to long-term monitoring and adaptive management.
REFERENCES:
Balch, J. K., Iglesias, V., Mahood, A. L., Cook, M. C., Amaral, C., DeCastro, A., Leyk, S., McIntosh, T. L., Nagy, R. C., St. Denis, L., Tuff, T., Verleye, E., Williams, A. P., & Kolden, C. A. (2024). The fastest-growing and most destructive fires in the US (2001 to 2020). Science, 386(6720), 425–431. https://doi.org/10.1126/science.adk5737
Brisco, E., Kulinskaya, E., & Koricheva, J. (2023). Assessment of temporal instability in the applied ecology and conservation evidence base. Research Synthesis Methods, November, 1–15. https://doi.org/10.1002/jrsm.1691
Flitcroft, R. L., Abell, R., Harrison, I., Arismendi, I., & Penaluna, B. E. (2023). Making global targets local for freshwater protection. Nature Sustainability. https://doi.org/10.1038/s41893-023-01193-7
George, M. M., Platts, S. V., Berry, B. A., Miller, M. F., Carlock, A. M., Horton, T. M., & George, M. H. (2024). Effect of SeaFeed, a canola oil infused with Asparagopsis armata , on methane emissions, animal health, performance, and carcass characteristics of Angus feedlot cattle. Translational Animal Science, 8(August). https://doi.org/10.1093/tas/txae116
Greenspoon, L., Krieger, E., Sender, R., Rosenberg, Y., Bar-On, Y. M., Moran, U., Antman, T., Meiri, S., Roll, U., Noor, E., & Milo, R. (2023). The global biomass of wild mammals. Proceedings of the National Academy of Sciences, 120(10), 2017. https://doi.org/10.1073/pnas.2204892120
REPLY AND COUNTER-REPLY TO GREENSPOON:
- Santini, L., Berzaghi, F., & Benítez-López, A. (2024). Total population reports are ill-suited for global biomass estimation of wild animals. Proceedings of the National Academy of Sciences, 121(4), 1–3. https://doi.org/10.1073/pnas.2308958121
- Greenspoon, L., Rosenberg, Y., Meiri, S., Roll, U., Noor, E., & Milo, R. (2024). Reply to Santini et al.: Total population reports are necessary for global biomass estimation of wild mammals. Proceedings of the National Academy of Sciences of the United States of America, 121(4), 1–2. https://doi.org/10.1073/pnas.2316314121
Jasechko, S., Seybold, H., Perrone, D., Fan, Y., Shamsudduha, M., Taylor, R. G., Fallatah, O., & Kirchner, J. W. (2024). Rapid groundwater decline and some cases of recovery in aquifers globally. Nature, 625(7996), 715–721. https://doi.org/10.1038/s41586-023-06879-8
Lang, M. W., Ingebritsen, J. C., & Griffin, R. K. (2024). Status and Trends of Wetlands in the Conterminous United States 2009 to 2019. U.S. Department of the Interior; Fish and Wildlife Service, Washington, D.C. 43 pp. https://www.fws.gov/project/2019-wetlands-status-and-trends-report
Langhammer, P. F., Bull, J. W., Bicknell, J. E., Oakley, J. L., Brown, M. H., Bruford, M. W., Butchart, S. H. M., Carr, J. A., Church, D., Cooney, R., Cutajar, S., Foden, W., Foster, M. N., Gascon, C., Geldmann, J., Genovesi, P., Hoffmann, M., Howard-McCombe, J., Lewis, T., … Brooks, T. M. (2024). The positive impact of conservation action. Science, 384(6694), 453–458. https://doi.org/10.1126/science.adj6598
Li, K., Fisher, J., Power, A., & Iverson, A. (2024). A map of pollinator floral resource habitats in the agricultural landscape of Central New York. One Ecosystem, 9. https://doi.org/10.3897/oneeco.9.e118634
Littlefield, C. E., Suraci, J. P., Kintsch, J., Callahan, R., Cramer, P., Cross, M. S., Dickson, B. G., Duncan, L. A., Fisher, J. R., Freeman, P. T., Seidler, R., Wearn, A., Andrews, K. M., Brocki, M., Dodd, N., Gagnon, J., Johnson, A., Krosby, M., Skroch, M., & Sutherland, R. (2024). Evaluating and elevating the role of wildlife road crossings in climate adaptation. Frontiers in Ecology and the Environment, 1–10. https://doi.org/10.1002/fee.2816
Pivello, V. R., Vieira, I., Christianini, A. V., Ribeiro, D. B., da Silva Menezes, L., Berlinck, C. N., Melo, F. P. L., Marengo, J. A., Tornquist, C. G., Tomas, W. M., & Overbeck, G. E. (2021). Understanding Brazil’s catastrophic fires: Causes, consequences and policy needed to prevent future tragedies. Perspectives in Ecology and Conservation, 19(3), 233–255. https://doi.org/10.1016/j.pecon.2021.06.005
Sutherland, W. J., Bennett, C., Brotherton, P. N. M., Butchart, S. H. M., Butterworth, H. M., Clarke, S. J., Esmail, N., Fleishman, E., Gaston, K. J., Herbert-Read, J. E., Hughes, A. C., James, J., Kaartokallio, H., Le Roux, X., Lickorish, F. A., Newport, S., Palardy, J. E., Pearce-Higgins, J. W., Peck, L. S., … Thornton, A. (2024). A horizon scan of global biological conservation issues for 2024. Trends in Ecology & Evolution, 39(1), 89–100. https://doi.org/10.1016/j.tree.2023.11.001
Trencher, G., Nick, S., Carlson, J., & Johnson, M. (2024). Demand for low-quality offsets by major companies undermines climate integrity of the voluntary carbon market. Nature Communications, 15(1), 6863. https://doi.org/10.1038/s41467-024-51151-w
UNEP-WCMC, 2024. State of the World’s Migratory Species. UNEP-WCMC, Cambridge, United Kingdom.
https://www.cms.int/en/publication/state-worlds-migratory-species-report
Wang, H., Liu, J., Klaar, M., Chen, A., Gudmundsson, L., & Holden, J. (2024). Anthropogenic climate change has influenced global river flow seasonality. Science, 383(6686), 1009–1014. https://doi.org/10.1126/science.adi9501
Sincerely,
Jon
p.s. I inherited that Christmas sweater from my dad, and typically only pull it out once a year for a Christmas sing-along
Monday, April 1, 2024
April 2024 Science Summary
Hello,
Just three articles this month: how wetland restoration affects climate mitigation, how climate change is affecting seasonality of river flow, and a summary of how people use plants around the world.
If you know someone who wants to sign up to receive these summaries, they can do so at http://bit.ly/sciencejon (no need to email me).
CLIMATE CHANGE:
Schuster et al. 2024 reviews the net climate impact of wetland restoration, considering carbon, methane, and nitrous oxide. Their headline is that it takes 525 years for restoring peat to result in net climate cooling (b/c short-term methane increases offset the carbon gains), and 141 years for non-peat wetlands (marshes, riparian wetlands, and swamps). They argue other more positive estimates have left out nitrous oxide. BUT they are looking just at the restoration over time NOT comparing restored wetlands to the baseline of degraded wetlands (since drained peat also emits methane and lots of CO2, the time would be a lot shorter to be net climate cooling. Some other papers I've read (e.g., Richardson et. al 2022 on pocosin) found minimal methane emissions making restoration a clear winner even in the short term. I asked a couple experts about this paper and they also flagged that while in the short term we should be worried about methane, it's also true that: the alkalinity export from peat could make them MORE cooling than we think, and that there are other ecosystem services to consider.
FRESHWATER:
Wang et al. 2024 looks at how climate change has changed the seasonality of river flow (how much it varies month to month, including frequency of droughts and floods). They found that ~14% of long-term river gauges show changes in seasonality over the last 50 years that isn't driven by changing annual precipitation. The surprise is that seasonality is mostly DECREASING counter to the narrative of more floods and droughts (see Fig 1 for a map of results, and Fig 2 which adds detail). In their figures brown means less seasonality (more even flow): "L+" means low flows become higher flows (NOT higher frequency of drought) while "H-" means floods see lower flood volume (again NOT lower frequency of flood events). You'll see most of North America, most of Europe, and some of Russia have seen reduced seasonality in recent decades. Blue means MORE seasonality, focused in: SE Brazil, some European countries, and in the US the SE and some of the Rocky Mountains. The explanation is worth reading in full, but in brief: 1) snow melting earlier means less runoff from snow at the same time as spring rains, 2) early spring greening means more water gets transpired, 3) it's more complicated in places not dominated by snowmelt.
PEOPLE AND NATURE:
Pironon et al. 2024 is a global analyis of plants used by humans (directly or indirectly - medicinal uses dominate but they look at nine other types of use, see Fig 2). See Fig 1a for a map of how many plant species are used around the world. They find 1) people use more plant species in places where most plant species exist, 2) Indigenous lands use slightly fewer species than neighboring non-Indigenous regions, and 3) protected lands use slightly fewer species than non-protected lands. These are correlations - they don't control for income or many other covariates. And from a conservation perspective we may not want all species to be used, especially rare ones!Note there are some problems with the data, e.g., Figure S1 shows how poor the sampling density is outside of the US, Central America, Europe, and Australia. Finally, they only found 971 species of plants that provide food to bugs we use (honeybees, silkworms, lac insects, and grubs) which seems really low. There's an article about this at: https://www.unep-wcmc.org/en/news/plants-and-their-contributions-to-people-are-insufficiently-protected-globally
REFERENCES:
Pironon, S., Ondo, I., Diazgranados, M., Allkin, R., Baquero, A. C., Cámara-Leret, R., Canteiro, C., Dennehy-Carr, Z., Govaerts, R., Hargreaves, S., Hudson, A. J., Lemmens, R., Milliken, W., Nesbitt, M., Patmore, K., Schmelzer, G., Turner, R. M., van Andel, T. R., Ulian, T., … Willis, K. J. (2024). The global distribution of plants used by humans. Science, 383(6680), 293–297. https://doi.org/10.1126/science.adg8028
Schuster, L., Taillardat, P., Macreadie, P. I., & Malerba, M. E. (2024). Freshwater wetland restoration and conservation are long-term natural climate solutions. Science of The Total Environment, 922(August 2023), 171218. https://doi.org/10.1016/j.scitotenv.2024.171218
Wang, H., Liu, J., Klaar, M., Chen, A., Gudmundsson, L., & Holden, J. (2024). Anthropogenic climate change has influenced global river flow seasonality. Science, 383(6686), 1009–1014. https://doi.org/10.1126/science.adi9501
Sincerely,
Jon
p.s. This photo is of a sculpture at the Kennedy Center by ByeongDoo Moon called "I have been dreaming to be a tree"