In an effort to reduce greenhouse gas emissions and curb global warming, the U.S. has enacted several ambitious federal laws, such as the Inflation Reduction Act (IRA) passed in 2022 and the Infrastructure Investment and Jobs Act (IIJA) of 2021.
These provide significant investments in clean energy projects and encourage technological innovations. Some analyses suggest they could reduce greenhouse gas emissions by more than 40% below 2005 levels by 2030.
However, in a paper published Jan. 16 in the journal Nature Climate Change, researchers at the University of Colorado Boulder and their collaborators suggest that these estimates may be overly optimistic, with everything from consumer decision-making to political polarization influencing how well they work.
“America stands at a pivotal moment with the passage of its ambitious climate legislation, said Leaf Van Boven, a co-author of the paper and a professor of psychology and neuroscience at CU Boulder. “The nation's ability to unite behind these transformative policies will either ignite a sustainable energy revolution or fumble into the familiar deadlock of political discord.”
The researchers said these climate laws will only have their intended effects if the invested money is deployed effectively.
For example, on the supply side, whether renewable energy infrastructure projects funded by these policies can be built at speed and at scale will affect how effective the policies are.
Currently, the average time for the federal government to issue a permit for a power transmission project in the U.S. is typically six to eight years.
Up to 80% of the IRA’s potential emissions reductions could be lost unless we can expand our power transmission network at twice the speed we have historically, according to Matt Burgess, the paper’s co-author, a fellow of the Cooperative Institute for Research and Environmental Sciences (CIRES) and director of the Center for Social and Environmental Futures (C-SEF).
“If it takes six to eight years to get a permit for a power line and even longer to get a utility-scale solar project approved, we might have almost no shovels in the ground in many key areas by 2035, when we're supposed to have already made significant progress,” Burgess said.
In addition, the team wrote in the paper that if these climate policies become too politically polarized that the next Congress repeals them or local governments refuse to spend the money, the policies will not be effective.
The researchers also proposed some potential solutions to reduce this resistance. For example, avoiding framing these laws as climate policies could reduce political polarization.
In a separate report published by C-SEF, Burgess and his team demonstrated that views on climate change played a significant role in whom people voted for when voters cast their ballots in the 2016 and 2020 presidential elections. The team concluded that the climate issue very likely cost Republicans the 2020 election, all else equal.
“This is obviously information that politicians and advocates across the political spectrum will want to know, heading into the 2024 election cycle,” said Burgess. “Beyond that, we don’t see it as our job as researchers to editorialize. How to reduce political polarization of climate change is one of the questions our research group is most interested in currently, and this provides some insight.”
JOURNAL
Nature Climate Change
ARTICLE TITLE
Supply, demand and polarization challenges facing US climate policies
ARTICLE PUBLICATION DATE
16-Jan-2024
Jingrui He, professor of information sciences at the University of Illinois Urbana-Champaign, has been awarded a two-year, $600,000 grant from the IBM-Illinois Discovery Accelerator Institute to improve modeling climate change and its impact across multiple application domains. He and a team of researchers from the University of Illinois and IBM will build Climate Runtime, a computational framework integrating cutting-edge capabilities from climate foundation models and multimodal fusion. This framework will allow for accurate prediction and quantification of weather and climate events and their impact in areas such as finance and agriculture.
“In agriculture, crop insurance data is shown to be strongly affected by historical global warming. Price fluctuation of greens and yield data demonstrate significant impacts by climate change,” said He. “For such multimodality data, we will leverage the geospatial representations from climate foundation models, fine-tune the predictive models to generate more reliable predictions in these domains as compared to state of the art, and explore deep insights regarding the key contributing factors.”
The researchers expect the Climate Runtime project to contribute to advances across multiple scientific disciplines, including artificial intelligence and climate science.
He’s general research theme is to design, build, and test a suite of automated and semi-automated methods to explore, understand, characterize, and predict real-world data by means of statistical machine learning. She received her PhD in machine learning from Carnegie Mellon University.
Climate change isn’t producing expected increase in atmospheric moisture over dry regions
Arid and semi-arid areas may face especially high risks of extreme heat and fire
Peer-Reviewed PublicationNATIONAL CENTER FOR ATMOSPHERIC RESEARCH/UNIVERSITY CORPORATION FOR ATMOSPHERIC RESEARCH
The laws of thermodynamics dictate that a warmer atmosphere can hold more water vapor, but new research has found that atmospheric moisture has not increased as expected over arid and semi-arid regions of the world as the climate has warmed.
The findings are particularly puzzling because climate models have been predicting that the atmosphere will become more moist, even over dry regions. If the atmosphere is drier than anticipated, arid and semi-arid regions may be even more vulnerable to future wildfires and extreme heat than projected.
The authors of the new study, led by the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR), are uncertain what’s causing the discrepancy.
“The impacts could be potentially severe,” said NSF NCAR scientist Isla Simpson, lead author of the study. “This is a global problem, and it’s something that is completely unexpected given our climate model results.”
Simpson and her co-authors say follow-up research is needed to determine why water vapor is not increasing. The reasons could have to do with moisture not moving from Earth’s surface into the atmosphere as projected or circulating around the atmosphere in unanticipated ways. It’s also possible that an entirely different mechanism could be responsible.
Adding to the mystery, the new study showed that while water vapor is increasing over humid regions of the world, it is not rising as much as expected during the most arid months of the year.
The study appears this week in the Proceedings of the National Academy of Sciences. The research was funded by the National Science Foundation, NOAA, and the U.S. Department of Energy. It was co-authored by scientists from the University of California, Los Angeles; University of California, Santa Barbara; Cornell University; Polar Bears International; and Columbia University.
A surprising finding
A basic rule of climate science is that the atmosphere can hold more moisture as it warms. This is known as the Clausius-Clapeyron relationship, and it’s the reason climate models consistently project that atmospheric water vapor will increase as the planet becomes warmer.
But when Simpson was working on a report for NOAA in 2020 about climate change in the southwestern United States, she realized that the atmosphere there had been drying much more than would be expected based on climate model simulations.
Intrigued, Simpson and her co-authors looked at the atmosphere globally to determine if water vapor was increasing in line with climate projections. The research team turned to multiple sources of observations from 1980 to 2020. These included networks of weather stations as well as datasets that estimate humidity based on observations from sources such as weather balloons and satellites.
To their surprise, the scientists found that water vapor over arid and semi-arid regions was generally remaining constant instead of increasing by close to 7% for every 1° Celsius (1.8° Fahrenheit) of warming, as would be expected based on the Clausius-Clapeyron relationship. Water vapor actually declined over the Southwest United States, which has seen a long-term reduction in precipitation.
“This is contrary to all climate model simulations in which it rises at a rate close to theoretical expectations, even over dry regions,” the authors wrote in the new paper. “Given close links between water vapor and wildfire, ecosystem functioning, and temperature extremes, this issue must be resolved in order to provide credible climate projections for arid and semi-arid regions of the world.”
The study noted that the situation is leading to an increase in vapor pressure deficit, which is the difference between the amount of moisture that the atmosphere can hold and the amount that’s actually in the air. When the deficit rises, it can act as a critical driver of wildfires and ecosystem stress.
“We could be facing even higher risks than what’s been projected for arid and semi-arid regions like the Southwest, which has already been affected by unprecedented water shortages and extreme wildfire seasons,” Simpson said.
She and her colleagues found a more complex situation in humid regions, where atmospheric water vapor increased as projected by climate models during wetter seasons. This increase leveled off somewhat during the driest months but did not flatten out as much as in arid and semi-arid regions.
Looking for the culprit
As for the question of why the water vapor in the atmosphere is not increasing over dry regions as expected, the authors broadly suggest two possibilities: the amount of moisture that is being moved from the land surface to the air may be lower than in models, or the way that the atmosphere is transporting moisture into dry regions may differ from the models.
Issues with atmospheric transport are less likely, they conclude, because that wouldn’t necessarily explain the common behavior among all arid and semi-arid regions worldwide, which receive moisture from differing locations.
That leaves the land surface as the most likely culprit. The authors speculate several possible causes: the land may have less water available to the atmosphere in reality than in models, it may be drying out more than anticipated as the climate warms, or plants may be holding on to moisture more effectively and releasing less into the atmosphere.
The authors also considered the possibility that there is an error in the observations. But they concluded this was unlikely since the discrepancy is closely tied to the dryness of regions all over the world, and it is consistently found even when dividing up the record into shorter time segments to avoid errors due to instrumentation changes.
Simpson emphasized that more research is needed to determine the cause.
“It is a really tricky problem to solve, because we don't have global observations of all the processes that matter to tell us about how water is being transferred from the land surface to the atmosphere," she said. "But we absolutely need to figure out what's going wrong because the situation is not what we expected and could have very serious implications for the future.”
This material is based upon work supported by the National Center for Atmospheric Research, a major facility sponsored by the National Science Foundation and managed by the University Corporation for Atmospheric Research. Any opinions, findings and conclusions or recommendations expressed in this material do not necessarily reflect the views of the National Science Foundation.
About the article
Title: “Observed humidity trends in dry regions contradict climate models”
Authors: Isla R. Simpson, Karen A. McKinnon, Daniel Kennedy, David M. Lawrence, Flavio Lehner, and Richard Seager
Publication: Proceedings of the National Academy of Sciences
On the web: news.ucar.edu
On X: @NCAR_Science
JOURNAL
Proceedings of the National Academy of Sciences
ARTICLE TITLE
Observed humidity trends in dry regions contradict climate models
In a new study, North Carolina State University researchers found that more extreme and frequent droughts would dramatically increase the amount of forest burned by wildfire in the southern Appalachian region of the Southeast through the end of the century.
In a study published in Fire Ecology, researchers found the most severe and frequent drought scenario would mean about 310 square miles of forest in the southern Appalachians burning every year in the decade ending in 2100. In comparison, there were around 231 square miles burned in 2016 in the mountain region – a year considered historic for wildfire in the southern Appalachians following multiple acts of arson, accidental ignitions and downed power lines.
“2016 was a watermark year for wildfire; we didn’t know we could have that much fire in the southern Appalachians,” said study co-author Robert Scheller, professor of forestry and environmental resources at NC State and associate dean for research in the NC State College of Natural Resources. “Under the most extreme conditions we forecasted, we would have the wildfire equivalent to that, or more, almost every year by the end of the century.”
In the study, researchers used computer modeling to project the total area burned by wildfire in the southern Appalachians of North Carolina, South Carolina, Georgia and Tennessee in 80 years across four scenarios that differed in terms of drought severity, and in terms of whether drought occurred in a year. They selected four of the most divergent outcomes in terms of drought intensity and timing that resulted from different climate warming models. All of the scenarios assumed high levels of greenhouse gas emissions that could cause between 2 and 7 degrees Celsius of climate warming on average by the end of the century, researchers said.
“All of our models fall under high emissions scenario, but there’s still a lot of uncertainty in how much warmer, and how much drier, the future is going to be, so we wanted to pick scenarios that were divergent,” said the study’s lead author Zachary Robbins, a former graduate student at NC State. “We also wanted to account for the fact that it’s anticipated that not only the amount of precipitation may change, but when precipitation occurs may dramatically change. Climate change is anticipated to give us very wet years and very dry years. Both of those are not ideal.”
Under the least extreme drought scenario, they projected a total of 231 square miles of forest would burn every decade through 2100 – which is similar to the outcomes they predicted under historical climate conditions. In the most extreme scenario of high drought intensity and high variability of drought year to year, the total area of forest burned would double within the next decade, and increase by approximately 900%, or nine times, by the end of the century. That would mean around 3,125 square miles of forest burning in the decade ending in 2100.
Across the entire 80-year period of the study, they projected a nearly five-fold increase in total area burned under the more extreme scenario, for a total of more than 17,000 square miles. They also saw that more intense drought had a bigger impact on total area burned than variability in drought.
“This was the worst outcome from the most extreme drought scenarios, but that more extreme scenario could be on the low-end of the future reality,” Scheller said. “The existing climate models have underestimated the current drought and heat conditions that we’ve seen in California recently. We should expect that impacts of climate change will be seen in big-step changes – the impacts can happen really fast.”
They also saw that the same areas of forest would burn more frequently. Currently, a single point in the forest will not see a fire again for around 800 to 1,200 years on average, researchers said. But under their extreme drought conditions, they projected that fires would return to certain forest points every five years by the end of the century. And even though they predicted more frequent wildfire, their model only predicted a marginal increase in fire-adapted tree species – without direct efforts to restore them.
“It’s not going to shift back, even as all these fires are happening,” Scheller said.
Spatially, they found that wildfires were concentrated in national forests, outside of the urban interface where there are more cities and homes. More specifically, the northwestern and southwestern areas of their study area had the highest concentrations of wildfire, representing the boundaries of the Chattahoochee-Oconee and Cherokee National Forests.
“Most of the wildfire is going to occur in isolated acres where it’s difficult to suppress them, away from roads,” Robbins said.
However, they also reported that with increases in forest area burned, it is more likely that fire would reach urban areas.
“We may feel somewhat insulated from these big changes in fire that we’re seeing on the West Coast, and while we may not see the scale and intensity of those fires, we are moving in the direction of a lot more fire,” Scheller said. “It’s going to be a more common phenomenon and concern, and it’s going to affect forests, wildlife, water and where people build homes.”
In future work, the researchers are planning to explore how much prescribed burns or fire suppression tactics could impact wildfire patterns and growth of fire-adapted tree species. In addition, they also want to look at whether programs to prevent arson or accidental human wildfire ignitions could make a difference.
“We need to be prepared for more anomalous years,” Scheller said. “It’s all about clarifying resources. Do we have the equipment and the people power to potentially respond to more frequent major fire years?”
The researchers said their findings are meant to inform plans for development, firefighting resources and forest management.
“Our study shows that we’d be moving from fire years being anomalous among the Southern Appalachians, to there being a possibly of a major fire year, with greater than 195 square miles burned in wildfire, in your average year,” Robbins said. “The point isn’t to scare people, or to try to tell people exactly what the future is. The point is to use this information to develop management plans so we can make better choices around development, firefighting and restoration activities.”
The study, “Fire regimes of the Southern Appalachians may radically shift under climate change,” was published online in Fire Ecology. Co-authors include E. Louise Loudermilk, Tina M. Mozelewski and Katie Jones. Funding was provided by the U.S. Forest Service Southern Research Station.
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Note to Editors: The study abstract follows.
“Fire regimes of the Southern Appalachians may radically shift under climate change”
Authors: Zachary J. Robbins, E. Louise Loudermilk, Tina M. Mozelewski, Katie Jones and Robert M. Scheller
Published: Jan. 12, 2024 in Fire Ecology
DOI: 10.1186/s42408-023-00231-1
Abstract: 1) The Southern Appalachians, United States, have historically experienced frequent fires but modern fire exclusion and fire suppression have made large fires rare. However, during a deep drought in 2016, the wildfire season resulted in multiple fires > 2,000 ha burning across the landscape. It is crucial that we understand how future drought may fundamentally alter the interaction of fire, ecology and society. 2) In order to understand how future climate change could alter wildfires and forest ecology in the Southern Appalachians, we assessed the influence of varying climate projections on potential shifts in the wildfire regime across the Southern Appalachians. We used four climate projections representing divergent drought patterns (overall drought trend, and interannual variability) within a parameterized, process-based fire model that captures the influence of climate, fuels, and fire suppression. 3) Compared to a historical climate, the total burned area (2020-2100) increased by 42.3 % under high drought variability, 104.8 % under a strong drought trend, and 484.7 % when combined. The variable spatial distribution of fire return intervals (FRI) illustrated the role of fire exclusion and suppression; some areas displayed multiple fires per decade, yet others experienced no fire at all. Overall fire severity was relatively stable under each climate scenario. More frequent fires corresponded with increased oak prevalence and a reduction in the biomass of mesic hardwoods and maple; however, mesic hardwoods remained prevalent under all fire intervals. Our study illustrates the long-term effects on landscape composition of the fire effects forecasted with future drought-fire interactions coupled with a history of fire exclusion. Synthesis: Increasing trends in drought magnitude and variability in the Southern Appalachians 3 may considerably increase wildfire activity, particularly in areas with minimal fire suppression, and have local scale fire effects that promote oak prevalence.
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Fire regimes of the Southern Appalachians may radically shift under climate change
ARTICLE PUBLICATION DATE
12-Jan-2024
