What will happen when the permafrost thaws?
Since the Industrial Revolution nearly 150 years ago, global average temperatures have increased by more than 1 degree C (1.9 degrees F), with the majority of that warming occurring since 1975. But during these recent decades of accelerated warming, temperatures in the arctic (latitudes above 66 degrees north) have have been rising even faster – nearly four times faster than the average global rate.
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On April 20, the Biden administration released a first-of-its-kind inventory of mature and old growth forests on federal lands, as had been mandated by an executive order on Earth Day last year. The inventory is technically sound and identifies more than 112 million acres of mature and old growth forest on land managed by the Forest Service and Bureau of Land Management—more than previous analyses, which is great news. This is a necessary first step toward protecting these important forests, but there are critical gaps that must be addressed as protections are designed.
First and foremost, the carbon storage and climate mitigation power of these forests should be front and center, but both go largely unmentioned in the latest report. Federal forests absorb the equivalent of roughly 3% of US emissions from fossil fuel burning each year, and mature and old growth forests are responsible for the majority of carbon uptake and storage. Multiple analyses by Woodwell Climate scientists and collaborators have found that the largest trees make up a small fraction of trees in a forest but store the majority of carbon. Furthermore, as intact forests mature, they accumulate even more carbon in soils.
In order to protect these mature and old growth forests, and the carbon and biodiversity they hold, we must identify the threats they face. The greatest threat facing national forests—and the one we most directly control—is logging; but here again, the latest report is largely silent. Instead, the focus is on warming-driven risks, especially fire. While it is vitally important to address climate risks, management actions to limit fire are not necessarily applicable in older forests. The body of evidence indicates that the best way to foster resilience to environmental disturbance, like fire, is to keep mature and old growth forests intact.
Further proposed rule-making and public comment opportunities are expected in coming days, and Woodwell Climate will be vocal in calling for protection of mature and old growth forests as the critical climate mitigation assets that they are.
STEM opportunities for young women
Adolescent girls show as much engagement as boys in science, tech, engineering and math, but this changes significantly when they reach college age. We discuss why young women aren’t pursuing these fields and some of the local opportunities to keep girls and young women engaged in STEM.
This year’s 100% water allocation in California does not mean the water crisis is over, experts say
Climate change will make it hard to predict how much water will come each year.
A recent paper, led by Woodwell Climate postdoctoral researcher Dr. José Safanelli, revealed that Brazil’s farms have been steadily moving out of the most suitable regions for agriculture—opening up a significant portion of the world’s agricultural production to vulnerability from the changing climate.
The study, published in Applied Geography, used an index to assess “Grain-cropping suitability” for two key staple crops—soy and maize. Suitability was determined by climatic factors (temperature and precipitation), as well as soil quality and terrain. The result was a continuous map detailing the areas of the country with the best biophysical conditions for growing crops.
Overlaying land use change data from the past two decades with this new map revealed a historical trend of agricultural lands expanding towards areas with poorer soil quality and lower suitability for grain-cropping, primarily in the north central and northeastern portion of the country.
Understanding Brazil’s agricultural migration
Farmers in Brazil have been moving north to this “agricultural frontier” since the 1980s— drawn primarily by economic opportunity, as well as the higher quality climate and terrain conditions along the southern edge of the Amazon.
Despite the favorable climate, the soil is inferior. Farmers are seeking cheap land, which often comes in the form of degraded pasture, originally created by clearing forest. Rainforest soils are not naturally nutrient rich and, without any additional inputs, the soil quality becomes depleted after just a few years. Many farmers know this fact, but come anyway. Dr. Safanelli has even seen this trend unfold within his own family.
“I was born in the south of Brazil, a region that has good soil conditions. Recently, two of my uncles who are farmers emigrated to Mato Grosso. There, the climate is wetter and more stable, but the soils are poor—depleted of nutrients.”
Additional research by Woodwell Climate Assistant Scientist Dr. Ludmila Rattis suggests that climatic advantage may be short-lived. Her work indicates that the climate in these areas is changing— becoming drier and hotter as global temperatures rise—and deforestation for agricultural expansion just makes the problem worse.
“We showed in our paper that these places have good climate and terrain suitability for now,” says Dr. Safanelli. “But they are restricted in soil quality. In Mato Grosso—the largest agricultural production state in Brazil—for example, the climate has been more stable and favorable than in other parts. The problem is that, according to projected climate scenarios, climate change may push these areas out of a good suitability space.”
What this means for agriculture in Brazil
Brazil is currently the world’s top producer of soy, and in the top three for maize. But this expansion into lower-suitability regions has introduced greater vulnerability into the agricultural system. Farmers already must provide greater investment in fertilizing the soil to make it productive, which cuts into their margins for profit. Add to that the fact that poor-quality soils, typically low in organic matter, can make crops less resilient to extreme heat and drought.
“Crop evapotranspiration—a process that directly governs crop growth and yield—depends on soil for absorbing rainfall and storing water. These marginal soils can make farmers more susceptible to climate change’s expected drier and warmer conditions, as they have limited capacity for storing water,” says Dr. Safanelli.
Reducing these vulnerabilities, Dr. Safanelli says, will require an integrated approach— improving land management practices and increasing crop yields on existing land to reduce the pressure to expand. “Reducing the vulnerability of croplands may be possible by adopting management practices that increase the resilience of the farming system, such as fully incorporating the principles of conservation agriculture, integrated production through agroforestry, crop-forest-livestock systems, or irrigation to control dryness. And perhaps allocating some of these marginal lands for land restoration, concentrating our resources in more highly suitable croplands.”
Carbon cycling is an essential part of life on the planet. Plants and animals use the element for cellular growth, it can be stored in rocks and minerals or in the ocean, and of course it can move into the atmosphere, where it contributes to a warming planet.
A new study led by Dr. Megan Behnke, a former Florida State University doctoral student and Woodwell Polaris Project participant who is now a researcher at the University of Alaska, found that plants and small organisms in Arctic rivers could be responsible for more than half the particulate organic matter (a carbon-rich nutrient) flowing to the Arctic Ocean. That’s a significantly greater proportion than previously estimated, and it has implications for how much carbon is sequestered in the ocean versus how much moves into the atmosphere.
Scientists have long measured the organic matter in rivers to understand how carbon cycles through watersheds. But this research, published in Proceedings of the National Academy of Sciences, shows that organisms in the Arctic’s major rivers are a crucial contributor to carbon export, accounting for 40 to 60 percent of the particulate organic matter—tiny bits of decaying organisms—flowing into the ocean.
“When people thought about these major Arctic rivers and many other rivers globally, they tended to think of them as sewers of the land, exporting the waste materials from primary production and decomposition on land,” said Dr. Rob Spencer, a professor in the Department of Earth, Ocean and Atmospheric Science at FSU, and collaborator on the paper. “This study highlights that there’s a lot of life in these rivers themselves and that a lot of the organic material that is exported is coming from production in the rivers.”
Scientists study carbon exported via waterways to better understand how the element cycles through the environment. As organic material on land decomposes, it can move into rivers, which in turn drain into the ocean. Some of that carbon supports marine life, and some sinks to the bottom of the ocean, where it is buried in sediments.
The study was supported by the Arctic Great Rivers Observatory, and it examines six major rivers flowing in the Arctic Ocean: The Yukon and Mackenzie in North America, and the Ob’, Yenisey, Lena, and Kolyma in Russia. Using data collected over almost a decade, they built models that used the stable and radioactive isotope signatures of carbon and the carbon-to-nitrogen ratios of the particulate organic matter to determine the contribution of possible sources to each river’s chemistry.
Not all particulate organic matter is created equal, the researchers found. Carbon from soils that gets washed downstream is more likely to be buried in the ocean than the carbon produced within a river. That carbon is more likely to stay floating in the ocean, be eaten by organisms there and eventually breathed out as carbon dioxide.
“It’s like the difference between a french fry and a stem of broccoli,” said Dr. Behnke. “That broccoli is going to stay in storage in your freezer, but the french fry is much more likely to get eaten.”
That means a small increase in a river’s biomass could be equivalent to a larger increase in organic material coming from the land. If the carbon in that organic matter moves to the atmosphere, it would affect the rate of carbon cycling and associated climate change in the Arctic.
“I always get excited as a scientist or a researcher when we find new things, and this study found something new in the way that these big Arctic rivers work and how they export carbon to the ocean,” Dr. Spencer said. “We have to understand the modern carbon cycle if we’re really going to begin to understand and predict how it’s going to change. This is really relevant for the Arctic at the rate that it’s warming and due to the vast carbon stores that it holds.”
The study was an international endeavor— a feature that, Dr. Behnke notes, is critical to Arctic work, especially as climate change advances.
“That pan-Arctic view of science is more important than ever,” Dr. Behnke said. “The changes that are occurring are far bigger than one institution in one country, and we need these longstanding collaborations. That’s critically important to continue.”
Protecting the planet
Scientists are urging drastic cuts to our fossil fuel use, saying we’re not on pace to avoid the worst impacts of climate change. As a result, some of them now support controversial technologies that could blunt the Earth’s rising temperatures, broadly known as geoengineering.
Watch on CBS Saturday Morning.
The little city that could
For Chelsea, Massachusetts, a new microgrid means energy resilience.
On a recent morning, researcher Dominick Dusseau offers a glimpse into the future of Chelsea, Massachusetts, a small, industrial city just across the Mystic River from Boston. On digital maps he displays over Zoom, great blue splashes cover large swaths of the city—areas where, by his calculations, climate-driven flooding is likely to occur. The maps depict a world where the locals who can least afford it will get hit the hardest.
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