What’s New?
Recent research has quantified the cumulative impact of dams on Brazil’s native savanna ecosystem, the Cerrado. The study created an index of the direct and indirect impacts of constructing hydroelectric facilities on both the rivers being dammed and the surrounding ecosystem.
While often offered as a cleaner alternative to fossil fuels, dams can have severe environmental impacts ranging from deforestation to obstruction of fish migrations, water pollution, and even direct greenhouse gas emissions resulting from inundation of the surrounding area. This study assessed these effects cumulatively, weighting them more heavily if multiple dams were present in a single watershed.
“For freshwater systems, there’s not the equivalent of a deforestation rate. We don’t have an easy metric of ecosystem damage. So this study was one way of building a method for assessing the unintended consequences of installing a dam in a Cerrado watershed,” says Woodwell Water program director Dr. Marcia Macedo, who collaborated on the paper.
The study puts forward a new Dam Saturation Index (DSI) for the region to approximate the environmental impacts of existing dams. High-saturation watersheds were concentrated in the central and western portions of the biome, and most planned dams are located in sensitive areas of native vegetation with little protection.
Understanding hydropower in Brazil
Hydropower is big in Brazil—66% of the country gets some or all of their energy from it. Harnessing the power of a river is often the easiest means of electricity production in rural and remote areas. However, large hydroelectric plants are more often used as a means of infrastructural support for extractive industries like mining, rather than to expand access to electricity for rural citizens. Conflicts have already arisen between communities and hydroelectric plants.
Conflict over water usage in the Cerrado is expected to increase as the region continues to get hotter and dryer due to human-caused climate change. Land use change in the biome has accelerated the impacts of climate change, removing the cooling and moisture-retaining effects of natural vegetation.
“There are a lot of dams already, and many more planned, and it’s only going to get more contentious as climate change continues,” Dr. Macedo says. “In the northern and eastern part of the Cerrado, it’s already quite dry. We’re already seeing conflict over water and these reservoirs could just make that worse as upstream locations are able to withhold water from those downstream.”
What this means for the Cerrado
The Cerrado has historically not garnered as much attention, or as many demands for its protection, as the neighboring Amazon rainforest. Less than 10% of the Cerrado is considered protected, and many of those protections are biased toward terrestrial habitats and species. Lack of research into the full impact of hydropower on the watersheds of the Cerrado has left the region vulnerable to unchecked development. Some dams have even been built in areas otherwise strictly protected. Dr. Macedo hopes this study will encourage a different attitude towards freshwater resources.
“There is a question of how we can innovate thinking about protecting freshwater systems, especially under climate change. They’re so important, and there are so many resources—fisheries and clean water and more—that come from these systems,” Dr. Macedo says.
This study focused on large hydroelectric dams, but Dr. Macedo notes that there are many more small dams, built to serve individual farms, that also impact the flow of headwater streams. Ongoing research is focused on understanding the cumulative impacts of dams of all sizes on tropical watersheds.
This study focused on large hydroelectric dams, but Dr. Macedo notes that there are many more small dams, built to serve individual farms, that also impact the flow of headwater streams. Ongoing research is focused on understanding the cumulative impacts of dams of all sizes on tropical watersheds.
What’s New?
The Cerrado is a tropical savanna located just southeast of the Amazon rainforest. This biome is a patchwork of forests, savannas, and grasslands, nearly as biodiversity rich as the Amazon yet suffering more due to lax environmental protections. Over 46% of its original land cover has already been cleared for crops or pastures. A recent study assessed the impacts of this conversion on the temperature and water cycling in the region.
The study found that clearing of natural ecosystems resulted in increased land surface temperatures and reduced evapotranspiration — water evaporated to the atmosphere both from soils and as a byproduct of plant growth. Across the biome, land use changes caused a 10% reduction in water being cycled into the atmosphere annually, and almost 1 degree C of warming. Where native savanna vegetation was cleared, temperatures increased by 1.9C and the water recycled to the atmosphere decreased by up to 27%. These changes don’t take into account the additional effects of atmospheric warming from greenhouse gas emissions.
The study also projects forward three potential future scenarios based on different levels of environmental protection. The worst-case scenario assumes an additional 64 million hectares of both legal and illegal deforestation, which would leave just 20% of native vegetation in the Cerrado by 2050. If illegal deforestation is prevented but legal deforestation still advances, an additional 28 million hectares of deforestation would continue to warm and dry out the region. Only in the most optimistic scenario, with enforced zero deforestation policies and restoration of over 5 million hectares of illegally cleared vegetation, would the impacts of past clearing begin to reverse.
“If we continue down this path of weakening environmental policies, we’re probably heading towards an uncontrolled increase in deforestation,” says Ariane Rodrigues, researcher at the University of Brasilia and lead author on the paper. “As a result, we could reach almost 1 C of temperature increase by 2050 from land use change alone. If we add the estimated temperature increase from global greenhouse gas emissions, we will have a critical situation for food production, biodiversity, water and wildfire risk, affecting areas located way beyond the biome’s limits.”
Understanding Land Use in the Cerrado
Incentives for large-scale commercial agriculture in the Cerrado date back to the 1970s. Despite its high biodiversity, only 11% of the Cerrado is protected and technological advancements provided favorable conditions for agriculture to expand rapidly.
The half of the biome that remains unconverted is considered prime agricultural land. The Cerrado alone is responsible for 12% of global soybean production and 10% of global beef exports. Growing demand for these agricultural products is pushing farmers and ranchers to expand into the Matopiba region in the Northeast Cerrado — one of the largest remaining areas of undisturbed native vegetation.
Hotspots of reduced evapotranspiration and increased temperatures can already be seen in areas of Matopiba with intensifying agricultural activity. This means that farms will rely even more heavily on irrigation to combat drought, a strategy made less viable by the warming and drying caused by agriculture itself.
“That is the driest portion of the Cerrado, where there’s the most climate risk already,” says paper co-author and Woodwell Water program director, Dr. Marcia Macedo. “You can see that in the data — it’s getting hotter, and there’s less evapotranspiration, so we are really intensifying conflicts in areas that are already on the edge.”
What this Means for Protecting the Cerrado
The results of the paper highlight the urgent need for a paradigm shift that values the additional services the Cerrado provides beyond just crop production. Not only does it house unique ecosystems, but it plays a pivotal role in modulating the climate of the region. In the best-case scenario evaluated by the paper, zero-deforestation and restoration policies could avoid extensive warming and drying and begin compensating for the past transformation of Cerrado landscapes. Continued conversion of natural vegetation will jeopardize both biodiversity and agricultural stability in the Cerrado, as crops struggle to be productive under hotter and drier conditions.
Already, conflicts over water usage and irrigation are occurring in western Bahía state. As the region warms and dries, competition for a scarce resource will become more common and large-scale agriculture will become much less viable.
“We’re making some risky decisions in terms of land use,” says Dr. Macedo, “We’re losing a lot for short term gains in crop production, often in areas that will struggle to sustain large-scale agriculture as climate changes.”
The Amazon rainforest is one of the planet’s best natural climate solutions. Roughly 123 billion tons of carbon are estimated to be stored in the trees and soils of the Amazon and, if protected, it has the power to continue sequestering billions of tons of carbon each year.
But that irreplaceable carbon sink is under steady threat from a cycle of deforestation, fire, and drought that is both exacerbated by and contributing to climate change. Preliminary analysis from Woodwell of last year’s data has outlined that the most vulnerable regions of the Amazon are where drought and deforestation overlap.
2021 data shows deforestation drives fire in the Amazon
Unlike temperate or boreal forest ecosystems—or even neighboring biomes in Brazil— fires in the Amazon are almost entirely human caused. Fire is an intrinsic part of the deforestation process, usually set to clear the forest for use as pasture or cropland. Because of this, data on deforestation can provide a good indicator of where ignitions are likely to happen. Drought fans those flames, producing the right conditions for more intense fires that last longer and spread farther. Examining the intersection between drought and deforestation in 2021, Woodwell identified areas of the Amazon most vulnerable to burning.
Areas of deforestation combined with exceptionally dry weather to create high fire risk in northwestern Mato Grosso, eastern Acre, and Rondonia. Although drought conditions shifted across the region throughout the course of the year, deforestation caused fuel to accumulate along the boundaries of protected and agricultural land.
These areas of concentrated fuel showed the most overlap with fires in 2021, indicating that without the ignition source that deforestation provides, fires would be unable to occur, even during times of drought.
In June of 2021, we identified a dangerous and flammable combination of cut, unburned wood and high drought in the municipality of Lábrea, that put it at extreme risk of burning. Data at the end of December of 2021 confirmed this prediction. The observed fire count numbers from NASA showed that last year, Lábrea experienced its worst fire season since 2012.
Fires and climate change form a dangerous feedback loop
As a result of deforestation in 2021, at least 75 million tons of carbon were committed to being released from the Amazon. When that cut forest is also burned, most of the carbon enters the atmosphere in a matter of days or weeks, rather than the longer release that comes from decay.
This fuels warming, which feeds back into the cycle of fire by creating hotter, drier, conditions in a forest accustomed to moisture. Drought conditions weaken unburned forests, especially around the edges of deforestation, which makes them more susceptible to burning and releasing even more carbon to the atmosphere to further fuel warming.
Fire prevention strategies enacted by the current administration over the past 3 years have been insufficient to curb burning in the Amazon, because the underlying cause of deforestation remains unaddressed. Firefighting crews are not sufficiently supported to continue their work in regions like Lábrea that are actively hostile to combating deforestation and fire. If deforestation has occurred, fire will follow. To ensure the safety of both the people and the forests in these high-risk municipalities, the root causes of deforestation must be addressed with stronger and more strategic policies and enforcement.
Woodwell workshop brings Indigenous firefighters to Brasilia
A week-long workshop encourages knowledge sharing between Indigenous Brazilian fire brigades
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.
Success or failure? Woodwell scientists deem COP26 a mixed bag
Glasgow Climate Pact alone is not enough to limit warming to 1.5 C, but COP26 made real progress
For the first two weeks of November, diplomats and scientists from around the world descended on Glasgow, Scotland for the United Nations’ 26th annual Conference of Parties—hailed by some as the “last, best, hope” for successful international cooperation on the issue of climate change. Woodwell sent three expert teams to push for more ambitious policies that integrate our understanding of permafrost thaw and socioeconomic risks, and for financial mechanisms to scale natural climate solutions. Here are their thoughts on the successes and failures of this pivotal meeting.
Bold pledges but uncertain follow-through for tropical forests
The conference started off with a bold promise from 100 nations to end deforestation by 2030, accompanied by a pledge of more than $19 billion from both governments and the private sector. Though similar pledges to end deforestation have failed in the past, the funding pledged alongside this one gives reason to be hopeful.
$1.7 billion of the funds are allocated specifically to support Indigenous communities, which Woodwell Assistant Scientist Dr. Glenn Bush believes is a big step forward, though creating policies that are equally supportive will be where the real work gets done.
“It’s particularly welcome that Indigenous peoples are finally being acknowledged as key protectors of forests. The real challenge, however, is how to deliver interlocking policies and actions that really do drive down deforestation globally and scale up nature-based solutions to climate change.”
Dr. Ane Alencar, Director of Science at IPAM Amazônia, said that, for Brazil, half of the solution could come from enforcing existing laws and designating public forests. The other half could come from consolidating protected areas, creating incentives for private land conservation, and providing technical support for sustainable food production.
Dr. Bush also presented the CONSERV project, a joint initiative between IPAM and Woodwell that provides compensation for farmers who preserve forests on their land, above and beyond their legal conservation requirements. Increasing the scale and financing of viable carbon market plans like CONSERV could be crucial in incentivizing greater forest protection.
Climate risk a growing focus for governments
During the second week of the conference, Woodwell released a summary report on a series of climate risk workshops with policymakers and climate risk experts from 13 G20 nations. These workshops, conducted in collaboration with the COP26 Presidency and the British government’s Science and Innovation Network, identified challenges to incorporating climate risk assessments into national-level policy, and the report made recommendations for moving from simply making the science available to making it useful for implementation. The report demonstrated a desire from policymakers to get involved in climate risk analyses early in the process, to ensure the information addresses a country’s particular needs.
One success of the conference was the creation of a new climate risk coalition, led by Woodwell. The coalition, composed of 9 other organizations, will produce an annual climate risk assessment for policymakers.
“Understanding the full picture of climate risk is incredibly important when you’re setting policy,” explained Woodwell’s Chief of External Affairs, Dave McGlinchey. “We also heard, however, that the climate risk assessments need to be designed with the policymakers who will eventually use them. This research must speak directly to their interests if it is going to be delivered effectively.”
The increased desire of policymakers to better understand and address oncoming climate risks demonstrates an important shift to viewing climate change as a present problem, rather than solely a future one.
Permafrost thaw presents the greatest remaining uncertainty in forecasting emissions
One risk that still isn’t high enough on the COP agenda is rapid Arctic change, particularly permafrost thaw. The Cryosphere Pavilion, hosted by the International Cryosphere Climate Initiative, convened conversations ranging from the implications of permafrost thaw, to environmental justice for Northern Communities and respecting Indigenous knowledge and culture. For Arctic Program Director, Dr. Sue Natali, the Indigenous-led panels were some of the most impactful of the conference. But postdoctoral researcher Dr. Rachael Treharne noted that, no matter how well attended, there’s a difference between being in the Cryosphere Pavilion and being on the main stage.
Woodwell was among a group of organizations pushing to get permafrost emissions the attention it demands. Emissions released by thawing permafrost are currently not accounted for in national commitments, but are potentially equivalent to top emitting countries like the U.S. November 4 at the conference was “Permafrost Day” and each event was at full capacity for the pavilion, signaling growing attention to permafrost science. Woodwell, alongside a dozen polar and mountain interest groups called for even more commitment to the cryosphere conversation at the upcoming Subsidiary Body for Scientific and Technological Advice U.N. climate conference in Bonn scheduled for June of 2022.
Even with this greater recognition of the seriousness of Arctic climate change, the region and its people are being hit much harder and faster than the rest of the globe. Slow-moving decision-making and talk without follow-through will seriously endanger Arctic residents.
“I left the COP having a very hard time feeling ‘optimistic’, while knowing that the hazards of climate change are already severely impacting Arctic lands, cultural resources, food and water security, infrastructure, homes, and ways of living,” said Dr. Natali. “After repeated years of record-breaking Arctic wildfires, heatwaves, and ice loss, I’m not sure how a 1.5 or 2C warmer world—one in which we know that these events will only get worse—is a reasonable goal.”
Though missing necessary milestones at COP26, climate action is accelerating
Overall, however, the final Glasgow Climate Pact fell short of the ambitious action the world needs in order to limit warming. The deal made several last-minute compromises surrounding the phase out of fossil fuels. COP president Alok Sharma said that, while a future with only 1.5 degrees of warming is possible, it is fragile—dependent on countries keeping to their promises.
Despite this, McGlinchey says there was real progress at COP26. The conference reached a resolution that earned the unanimous agreement of all attending parties. The formal process has also begun to accelerate, with nations required to return with more ambitious climate mitigation plans next year, rather than on the previous five year timeline.
“We are not yet where we need to be,” McGlinchey said. “But we are better off than where we were two weeks ago. Let’s keep going.”
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