Forests are one of our best natural climate solutions for combating increasing global temperatures. A recent study from researchers at the University of Virginia and Woodwell Climate Research Center found that avoiding tropical deforestation could prevent more than 1 degree Celsius of atmospheric warming.
About 75% of that temperature change comes from the release of carbon stored in the large old growth forests. But there is another 25% that comes from changes in biophysical properties, of forests.
One important biophysical property is evapotranspiration. Through photosynthesis, plants release water vapor into the air that contributes to cooling near the ground, and cloud formation higher in the atmosphere, that reduces incoming solar radiation.
A second biophysical property is the roughness of the tree canopy, which disrupts air flow above the forest. The more uneven the canopy, the more turbulent the air, which disperses heat away from the surface. In the tropics, evapotranspiration and canopy roughness are high, which means that surface temperatures remain relatively low and dispersed throughout a deep atmosphere.
The picture gets more complicated when you factor in compounds called biogenic volatile organic compounds (BVOC) that forests naturally produce. These compounds can either contribute to cooling by encouraging the formation of clouds, or to warming by creating ozone and methane. In the tropics, the net effect of BVOCs is cooling.
Outside of the tropics, different biophysical effects dominate. In the Arctic, the ability of different surfaces to reflect energy plays a large role in regional cooling. Features like snow cover can dramatically impact the amount of reflection.
The study shows that protecting forests is vital to combating climate change. Forests are not only key to storing and sequestering carbon, but also to regional adaptation as temperatures rise. Their innate properties keep us cool.
The city of Chelsea, Massachusetts persevered through the American Revolution and two great fires. Now its resilience is being tested by climate change, as rising sea levels and more intense storms have begun sending frequent flood waters into the city.
Woodwell Climate Research Center recently conducted a thorough analysis of flood risk in Chelsea, identifying where flooding is likely to increase with climate change. The picture it paints is one where the city’s most vulnerable citizens get hit the hardest.
Located north of Boston where Chelsea Creek merges into the Mystic River and the Boston Harbor, Chelsea is vulnerable to two forms of flooding— storm surge from the harbor and extreme rainfall events. Currently, 15% of the city falls within an area of potential flooding. That number will more than double to 34% by 2081.
The return interval of high intensity flooding events will also increase. Scientists use the term “1-in-100 year events” to refer to the kind of large-scale flooding that has a 1% likelihood of occurring over the course of a century. Woodwell calculated that today’s 1-in-100 year rainfall events could become three times as likely by mid-century, and 1-in-100 year storm surge events could be annual occurrences by 2081. That would be like the city of Chelsea experiencing flooding proportional to Hurricane Sandy every year.
Chelsea was settled on a salt marsh punctuated by five hills. The city was developed from the high ground down, and much of the marsh and wetlands around Island End and Chelsea Creek were filled in over the city’s history. These low lying areas form the city’s vulnerable floodplain.
According to Woodwell’s analysis, that floodplain contains much of the city’s vital industry. Two oil terminals sit on Chelsea’s waterfront— the Chelsea Sandwich and Gulf Oil terminals. Here, petroleum, natural gas, and other petrochemicals are stored before being transported to their final destinations. The southeastern waterfront is also a designated port area for commercial shipping.
On the western side of the floodplain is the New England Produce Center, a massive regional hub for food distribution, as well as a major employer.
“Our waterfront has been industrial for 200 years and will continue to be industrial. But we’re very concerned that industry and flooding aren’t compatible,” says Karl Allen, a planner in Chelsea’s Department of Housing and Community Development who worked with Woodwell on the analysis.
Affordable housing is also at risk. Much of the city’s affordable housing was built in the 50’s and 60’s in the lowest-lying areas of the city, where marshes were filled in to create land for their construction. These communities are already familiar with bearing the burden of environmental damages— a rail line bisects the city through a designated environmental justice corridor. At only a few feet above sea level, the rail line serves as a major inundation pathway. Without adaptation measures, climate change will hit these lower income areas hardest.
“I can say that the one thing that’s been very common for municipal and state agencies is a sense of moving goalposts,” says John Walkey, the Director of Waterfront and Climate Justice Initiatives for GreenRoots. GreenRoots is a community organization dedicated to improving urban environmental and public health in Chelsea. Walkey and Greenroots facilitated the collaboration between Woodwell and the city.
“We are now at the stage where climate processes are moving faster than our bureaucracy can,” said Walkey. That could have been a paralyzing realization, especially backed up with analysis results outlining the intensity of increased flooding. Instead, the City’s planning leaders have decided to confront the floodwaters head on, using the analysis to change the way they think about implementing routine infrastructure updates.
Of course, Water doesn’t care where one municipality begins or ends; it will flow into any accessible space. The success of Chelsea’s adaptation measures will depend on collaboration with nearby localities— Everett, Revere, Boston. For example, there are plans in the works to construct a flood defense between Chelsea and nearby Everett that sits across the Island End River. Both cities hope this landscaped wall will protect the area from major flooding until at least 2070.
Having a thorough flood risk analysis also puts the city in a good position to lobby for adaptation on a larger scale. In mid-April, Woodwell and Chelsea hosted a briefing for the offices of Massachusetts Senators Ed Markey and Elizabeth Warren and Congresswoman Ayanna Pressley on the results of the flood analysis and the regional security issue it represents.
“Chelsea is facing a severe threat from climate change over the course of the next 50 years,” said Chelsea City Manager, Tom Ambrosino during the briefing. “So we are working hard to try to be prepared for it. But a lot of these projects are beyond our immediate capability.”
There are hundreds of Chelseas across the United States facing similar, and increasingly urgent, threats from flooding, drought, heat, or extreme weather. Many communities are scrambling to adapt as disasters hit, without knowing how much more change is on the horizon. Replicating climate risk analyses like the one in Chelsea could help them get a more specific picture of what they are facing.
“When you tell people well, ‘you’ve got to design for conditions in 2070’, they say ‘what does that mean? What kind of storm are we designing for?” says Allen. “This analysis has given us a better understanding of what kind of disasters we’ll be looking at, and with what frequency, so we have a design target.”
Risk analyses are invaluable to a municipality’s ability to plan for the shifting goalposts of climate change. Yet the availability of these analyses is uneven. Cities with more resources are able to pay private companies for risk assessments, while non-profits like Woodwell work to fill in the gaps. The Center has already partnered with 14 communities in the U.S. and abroad to produce tailored analyses. But there are nearly 20 thousand municipalities in the U.S. alone. Each will experience their own unique version of climate change.
“It really highlights the need for a national climate service,” said Woodwell Research Associate Dominick Dusseau who worked on the analysis for Chelsea, “something that can provide a nationwide standard service, rather than a piecemeal thing.”
Woodwell’s analysis is a prototypical version of what could be possible with more uniform risk assessment services, as well as a model of successful community engagement. Woodwell will continue to grow its partnerships with individual cities, but the scope of climate change will require a larger, more coordinated response.
“We’re doing a lot, there’s just so much more to do,” says Dusseau.
A recent study, published in Proceedings of the National Academy of Sciences (PNAS), has quantified the unrealized potential of land-based carbon storage. A series of maps shows that both plants and soils have the potential to store 287 billion metric tons more across the globe— more than the current annual emissions of the European Union.
“From forests to soils, terrestrial ecosystems store enormous amounts of carbon globally, and are capable of storing even more,” said Dr. Wayne Walker, Carbon Program Director at Woodwell Climate Research Center and study lead author. “But realizing the untapped potential of land to aid in addressing the climate crisis means understanding how much storage space is available, where in the world that space is located, and what actions can be taken in those places to take advantage of the opportunity they offer as rapidly as possible. This study provides the data and conceptual framework for doing that.”
These findings reveal the significant potential for expanding land-based carbon capture globally through protection, restoration, and improved management of forests and other woody systems. Improved management of existing forests alone may offer more than 75% of the untapped potential, with the vast majority (71%) of it concentrated in tropical ecosystems.
“Forest stewardship represents the greatest opportunity for realizing carbon removal and storage in the near term, and the urgency of the climate crisis demands that we prioritize these efforts,” said Peter Ellis, Director of Natural Climate Solutions Science at The Nature Conservancy and study co-author. “Our research shows that after safeguarding lands required for food production and human habitation, improved management of forests and other woody systems — particularly degraded forests across the global tropics — offers tremendous climate mitigation potential.”
The study is timely, coming on the heels of the Intergovernmental Panel on Climate Change (IPCC)’s Working Group III’s latest report, which focuses on the urgent need to reduce carbon emissions in order to limit future warming, and highlights the significant mitigation potential of natural and managed ecosystems given the opportunity they offer to remove additional carbon from the atmosphere. While study results point to the significant opportunity that land offers as a natural climate solution based on what we know now, this work cannot stop there. Future research should build off these findings to support development of policies that take full advantage of the available land-based carbon sink.
“We anticipate these findings will prove valuable for many countries, since natural climate solutions figure heavily in delivering Paris Agreement commitments in most countries. However, these results must be combined with a range of other information to prioritize and effectively implement natural climate solutions.” said Bronson Griscom, Senior Director of Natural Climate Solutions at Conservation International.
In March, the U.S. Securities and Exchange Commission issued a draft ruling on the regulation of corporate climate risk disclosure. The ruling requires that corporations disclose relevant climate risks and greenhouse gas emissions associated with operations, as well as include climate-related metrics in audited financial statements.
Last year, during the drafting process, the SEC requested public comments on the proposed rule. Woodwell Climate Research Center and Wellington Management coordinated a response, pushing for transparent, thorough, and accurate climate risk assessments and disclosure.
The proposed rule is open for public comment until June 17, 2022, and Woodwell is once again working alongside Wellington Management to coordinate comments.
“The SEC has recognized the importance of climate risk to financial systems, and they are moving forward. This is excellent progress, but for these new rules to be effective they need to hear from climate scientists and climate risk experts,” said Woodwell’s Chief of External Affairs, Dave McGlinchey.
In order to be effective, risk disclosures need to be standardized and consistent between corporations. Additionally, transparency is important in the risk assessment process, to ensure corporations are using comparable, science-backed models to accurately report on risk.
“If the SEC doesn’t provide guidelines on how physical climate risk is assessed, the rules will be toothless and corporations will be able to pay for the results that they want. We are looking to avoid a race to the bottom,” McGlinchey said.
Springtime in the Northern hemisphere is a momentary respite for many places—a pause before the heat of summer and potential for drought and fire. This year, however, summer arrived early, bringing with it scorching temperatures and out-of-control fires that have made national and international headlines.
Portions of India and Pakistan already have experienced record-setting heat. Unseasonably warm weather began in March, when India recorded the hottest monthly temperatures that the country has seen in the past 122 years—hitting an average maximum of 33.1 degrees Celsius (91.6 Fahrenheit). The heatwave continued with the third hottest April on record. The hottest time for India is typically May and June, before the monsoon season begins.
In addition to the early start of summer temperatures, this heat wave is particularly concerning for its scope. The heat has settled over most of India as well as parts of neighboring Pakistan for two months.
“The most shocking part for me has been the geographical extent and the duration,” said Woodwell Assistant Scientist, Dr. Zach Zobel in an interview with CNBC.
The heat-related death toll in Maharashtra state, the second-most populous state in India, has already reached 25. Heat waves like this one become particularly dangerous when humidity is high—preventing the human body from cooling itself through sweat and evaporation.
Earlier and more intense heat waves also have the potential to disrupt India’s crop yields, particularly heat, which is vulnerable to hot, dry weather. As climate change progresses unchecked, extreme heat waves like this one will become more and more common.
On the other side of the globe, rising temperatures have resulted in a rash of destructive fires well before the usual summer season. The state of New Mexico is currently fighting 20 separate fires in 16 counties. Two, the Hermit’s Peak and Calf Canyon fires, recently merged into the state’s second-largest wildfire on record, which has been burning now for more than a month.
The merged “megafire” has destroyed at least 276 structures and forced the evacuation of nearly 13,000 residences.
New Mexico is used to a fire season that starts in May or June. Climate change is making out-of-season fires more common and big fires were seen this year in Colorado and California as early as December and January. The United Nations declared a global wildfire crisis in February.
Climate change is warming and drying out western U.S. states, increasing the number of “fire weather days.” This has made fire management harder, limiting the possible timeframe for prescribed burns that reduce fuel loads. Intense winds also played a large role in fanning the New Mexico fires, one of which began as a prescribed burn that escaped.
As temperatures rise, the risks from deadly heatwaves and wildfire are growing. Fire seasons and extreme heat seasons are lengthening, frequently starting earlier and ending later, giving the land no time to recover from dry winters or the prior year’s heat. The response to both the fires in New Mexico and heat in India and Pakistan is the same—rapidly reducing global emissions by 15% every year to hit the IPCC target of 1.5 degrees of warming.
“There is no question that heat waves are made worse by fossil fuels and climate change everywhere in the globe,” said Dr. Zobel. “India and Pakistan are two of the hottest places in the world and will likely continue to see heat waves of this magnitude and worse over the next several decades.”
On March 28, 2022, firefighters from Indigenous communities across Brazil gathered in Brasília, the country’s capitol, for a week-long geography and cartography workshop. The workshop, a collaboration between the Coordination of Indigenous Organizations of the Brazilian Amazon (COIAB) and the Amazon River Basin (COICA), IPAM Amazônia, and Woodwell Climate Research Center, walked participants through the basics of using Global Information Systems technology to monitor and manage their own lands and forests.
Forests and native vegetation on Indigenous lands have been sustainably managed for millenia, and studies have found Indigenous stewardship of forests is an effective measure for preventing deforestation and degradation. Escaped fires can present a threat to forests, and many Indigenous communities have their own brigades that work on detecting and preventing runaway fires. In some places, prescribed burns are used as a tool for shaping and cultivating the land.
Participants attended from Indigenous lands located in a variety of Brazilian landscapes—from the Cerrado to the heart of the Amazon. Despite differences, participants found learning from other Indigenous communities extremely valuable.
“People came with a variety of skill sets,” said Woodwell Water Program Director Dr. Marcia Macedo. “What was most meaningful for participants was seeing other people like them, who do the same work and are also Indigenous people, already dominating material, knowing how to make the maps, and helping others. It gave them confidence that they could also figure it out.”
After a day of introduction to the core concepts of GIS and mapping, participants headed out to Brasília National Park to test their newfound skills. They visited burned areas from both an escaped fire and a prescribed burn, compared the two, marked GPS points, and took pictures. The data gathered on the field trip was used over the next few days to practice making maps.
“The goal was to not only teach the theory and help them understand the steps for making maps, but also mainly to develop the skills for them to be able to apply to their own lands on their own time,” said Woodwell postdoctoral researcher, Dr. Manoela Machado, who helped organize the event.
The workshop also fostered discussions about the complexity of management when fire can be both a threat and a tool. Because fire manifests differently in different biomes, well-managed fires look different for each community.
“On the final day, we had a discussion of values. Is fire good or bad? For whom—ants, forests, human health?” said Dr. Machado. “You can’t just criminalize fire if it’s a part of traditional knowledge and used as a tool for providing food, for example. So it’s a complex issue.”
Dr. Machado hopes the conversations will continue. She says the goal would be to host this workshop again to expand its reach, potentially beyond Brazil to include participants in other Amazonian countries.
A recent paper from Woodwell’s Tanguro Ranch Research Station has quantified a property locked into Brazil’s deep tropical soils that protects streams and rivers from the effects of fertilizer leaching and runoff. The study, led by Dr. Alexandra Huddell, a graduate student at Columbia University at the time of the study and now a postdoctoral fellow at the U.S. Environmental Protection Agency, estimated that, if well managed, Amazonian soils could continue to hold back excess nitrogen from reaching surface waters for many years, allowing for increased crop yields with relatively little impact on the surrounding ecosystem.
In temperate croplands—the midwestern U.S. breadbasket for example—some of the nitrogen in fertilizer that isn’t taken up by plants is converted to nitrate. Nitrate moves rapidly through soil and into groundwater, streams, and rivers. Excess nitrate threatens drinking water and causes algal blooms that can lead to low oxygen levels in lakes and coastal waters of oxygen.
But studies of the soils in Tanguro showed a very different dynamic. At Tanguro, the nitrate was sticking to the soil, not moving down towards groundwater and streams. Dr. Huddell’s study quantified the mechanism that led to such a stark difference between Tanguro’s soils and those of temperate cropland regions.
“We often think about increased agricultural intensification leading to decreases in local water quality, and this is an interesting case study of why that is not happening as quickly in Brazil,” said Dr. Huddell.
The difference is due to a molecular property inherent in the soil called “anion exchange capacity.”
Clay soils like the ones under the croplands of Tanguro and much of the Amazon rainforest form over millennia of intense weathering in the hot, wet climate, Huddell explained. Weathering produces minerals that impart positive charges to tiny soil particles. Nitrate, a negatively-charged ion (anion) then adheres to the positively charged soil. Most temperate zone soils are less weathered and have more negatively charged particles that repel nitrate–allowing it to move quickly to groundwater and streams.
Tanguro’s soils extend ten or more meters deep and have a large capacity for binding nitrate. That inherent property of the soil does not change when a forest is converted to agriculture.
“The mineral and structural composition of the soil don’t change much during conversion from forest to cropland, so the nitrate-retaining property is still present,” Woodwell Senior Scientist and co-author of the study, Dr. Christopher Neill says.
Dr. Huddell calculated that in this region, that capacity could last potentially for decades based on laboratory measurements. The precise timing will depend on factors like how much fertilizer is applied to croplands, whether water flows through some pores in the soil more than others and therefore bypasses portions of this anion exchange capacity, or if soil compaction at the surface reduces the water’s infiltration into the soil.
This finding has implications for slowing deforestation. Increasing crop yields on already converted land could increase Brazil’s agricultural output without destroying more of the Amazon Rainforest— a vital carbon sink. But intensification of fertilizer use only makes sense if it does not come at the expense of healthy freshwater ecosystems.
“If soils are well managed, you have this natural asset to keep the nutrients out of the water in ways we don’t have in the temperate zone,” Dr. Neill says. “We can likely intensify with more fertilizer use up to some level, and that will allow more food to be grown on less land, which could spare additional forest, but we need to better understand what those fertilizer limits are.”
Further investigation at Tanguro will test the limits of this capacity to narrow down the true size of this buffer.
A recent paper, published in Science Advances, has found that fires in North American boreal forests have the potential to send 3 percent of the remaining carbon budget up in smoke. The study, led by Dr. Carly Phillips, a fellow with the Union of Concerned Scientists (UCS), in collaboration with the Woodwell Climate Research Center, Tufts University, the University of California in Los Angeles, and Hamilton College, found that burned area in U.S. and Canadian boreal forests is expected to increase as much as 169 and 150 percent respectively—releasing the equivalent annual emissions of 2.6 billion cars unless fires can be managed. The study found proper fire management offers a cost-effective option, sometimes cheaper than existing options, for carbon mitigation.
Boreal forests are incredibly carbon rich. They contain roughly two-thirds of global forest carbon and provide insulation that keeps permafrost soils cool. Burned areas are more susceptible to permafrost thaw which could in turn release even more carbon into the atmosphere. Although fires are a natural part of the boreal ecosystem, climate change is increasing the frequency and intensity of them, which threatens to overwhelm the forest’s natural adaptations.
Despite the value of boreal forests for carbon mitigation, the U.S. and Canada spend limited amounts of funding on fire suppression, usually prioritizing fire management only where people and property are at risk. Alaska accounts for one fifth of all burned area in the U.S. annually, but it receives only 4 percent of federal funding for fire management. Limiting fire size and burned area through proper management can be effective at reducing emissions.
To prevent worsening emissions, fire management practices will have to be adjusted to not only protect people and property, but also to address climate change. Fire suppression in boreal forests is an incredibly cost-effective way to reduce emissions. The study found that the average cost of avoiding one ton of carbon emissions from fire was about $12. In Alaska, that means investing an average of just $696 million per year over the next decade to keep the state’s wildfire emissions at historic levels.
Increasing wildfires also pose an outsized threat to Alaska Native and First Nations communities, who may become increasingly isolated, and may lack the resources to evacuate quickly if wildfire encroaches on their lands. Many Alaska Native people already play a crucial role in existing wildfire crews, and investing in more fire suppression could create additional job opportunities for Indigenous communities.