To stabilize the Earth’s climate for people and ecosystems, it is imperative to ramp up natural climate solutions and, at the same time, accelerate mitigation efforts across the energy and industrial sectors, experts argue in a new article.
Among their findings, the researchers warn that a ten-year delay in emissions reductions from energy and industry could this century result in emissions that negate the net potential emissions reductions benefit of natural climate solutions.
Christa M. Anderson, Ruth S. Defries, Robert Litterman, Pamela A. Matson, Daniel C. Nepstad, Stephen Pacala, William H. Schlesinger, M. Rebecca Shaw, Pete Smith, Christopher Weber, Christopher B. Field. Natural climate solutions are not enough. Science, 2019; 363 (6430): 933-934 DOI: 10.1126/science.aaw2741
Background from Ellie: Conservatively, managing agricultural soils for soil organic matter can sequester 5 billion tons (Gt) of CO2e out of the atmosphere globally every year, drawing down 50% of what is needed to return to a safe climate by 2050.
The UN IPCC’s recent 1.5C report called soil carbon sequestration as among the cheapest methods with the greatest potential (http://www.ipcc.ch/report/sr15/). Healthy soils are foundational to human well-being, climate stabilization and vibrant ecosystems. The sustainable management and restoration of soils enhance agricultural productivity, fresh water availability, biodiversity, and climate change preparedness with enormous potential to slow and reverse negative impacts such as droughts, floods and more (von Unger, M. & Emmer, I. 2018. Carbon Market Incentives to Conserve, Restore and Enhance Soil Carbon. Silvestrum & TNC).
all IPCC scenarios that keep us below 2°C of warming include CO2 removal –
typically about 10 billion tons CO2 yr-1. Based on the latest estimates from
the IPCC, soils management could conservatively pull 5 billion tons of CO2 out
of the atmosphere annually on croplands and rangelands by 2050, offering 50% of
the needed carbon removal, with zero additional land and water use (D. Bossio,
TNC; and, Zomer et al. Global Sequestration Potential of Increased Organic
Carbon in Cropland Soils. Scientific Reports 7.;
Vermeulen et al, A Global Agenda for Action on Soil Carbon. Nature Sustainability, Jan 2019). Equally important is avoiding future
emissions from soil by protecting existing soil carbon stocks in grasslands and
Nearly half of all insect species worldwide are in rapid decline and a third could disappear altogether, according to a study warning of dire consequences for crop pollination and natural food chains.
…”We estimate the current proportion of insect species in decline—41 percent—to be twice as high as that of vertebrates,” or animals with a backbone, Francisco Sanchez-Bayo of the University of Sydney and Kris Wyckhuys of the University of Queensland in Australia reported.
“At present, a third of all insect species are threatened with extinction.”….
….Experts estimate that flying insects across Europe have declined 80 percent on average, causing bird populations to drop by more than 400 million in three decades.
Only a few species of insects—mainly in the tropics—are thought to have suffered due to climate change, while some in northern climes have expanded their range as temperatures warm.
In the long run, however, scientists fear that global warming could become another major driver of insect demise….
They found that the largest gains in yield occurred between concentrations of 0.1 percent and 2 percent of soil organic matter. “…we now have numbers, not just unverified ideas, that if you build organic matter you can improve outcomes — such as less fertilizer and increased yield.”
Emily E. Oldfield, Mark A. Bradford, Stephen A. Wood. Global meta-analysis of the relationship between soil organic matter and crop yields. SOIL, 2019; 5 (1): 15 DOI: 10.5194/soil-5-15-2019
While policymakers often tout the benefits of increasing soil organic matter as a way to boost agricultural yield, there is limited evidence that this strategy actually works. A new study quantifies this relationship, finding that greater concentrations of organic matter indeed produce greater yields — but only to a certain point.
Specifically, they find that increasing soil organic carbon — a common proxy for soil organic matter — boosts yields until concentrations reach about 2 percent, at which level they tend to hit a saturation point. Thereafter, the researchers say, the increase in SOM begins to deliver diminished returns.
Even still, they find that roughly two-thirds of agricultural soils dedicated to two of the world’s most important staple crops — maize and wheat — fall below that 2-percent threshold, suggesting the vast potential for agricultural policies that promote increased soil organic matter.
…It is well understood that building and maintaining soil organic matter is key to soil health. (SOM refers to organic matter found in the soil, including plant and animal materials that are in the process of decomposition.) It strengthens the capacity of soils to retain water and nutrients, supports structure that promotes drainage and aeration, and helps minimize the loss of topsoil through erosion.
For years, policymakers have emphasized the role of soil organic matter in a series of programs, including the “4 per 1,000” initiative of the Soils for Food Security — which emerged from the COP21 negotiations — and the U.S.’s “Framework for a Federal Strategic Plan for Soil Science.”
And yet when it comes to its role in promoting crop production, there’s been a surprising dearth of quantitative evidence, Bradford says. For Bradford, this gap in knowledge has been a nagging concern for nearly a decade; a 2010 National Research Council report on sustainable agriculture described organic matter as the cornerstone of most sustainability and soil quality initiatives, he recalls, yet offered no information on how much was actually needed to increase crop yields and reduce fertilizer application.
he solar panels in the fields at the University of Massachusetts Crop Research and Education Center don’t look like what most of us have come to expect. Instead of hunkering close to the earth, they’re mounted seven feet off the ground, with ample room for farmers or cows to wander underneath. Panels are separated by two- and three-foot gaps, instead of clustering tightly together. Light streams through these spaces and, underneath, rows of leafy kale and Brussels sprouts replace the typical bare earth or grass.
This unusual arrangement is one of the first examples of a dual-use solar installation—sometimes called agrivoltaics. It’s a photovoltaic array that’s raised far enough off the ground and spaced in such a way that some crops can still grow around and beneath the panels. The goal is to help farmers diversify their income through renewable energy generation, while keeping land in agricultural use and reducing greenhouse gas emissions….
“It’s too hard and too uncertain,” has long been the response of policymakers and investors in response to working on ways to conserve and improve carbon in soil. But, recent new momentum summarised in a paper in Nature Sustainability and authored by actors from government, science and the private sector offers hope in the form of technical, policy and ﬁnancial opportunities for rapid progress.
Building soil organic carbon helps water cycling, agricultural productivity, as well as climate change mitigation and adaptation. The amount of soil carbon globally is triple that of the atmosphere, making soil a useful tool for combatting climate change. A new global analysis … shows that building soil organic carbon on all corn and wheat lands could close the yield gaps for those crops by between 1/3 and 2/3 while also minimizing dependence on synthetic fertilizers.
“Momentum for action on soil organic carbon is indeed growing in political, financial and technical circles to address multiple sustainability goals, but not nearly fast enough.” says Deborah Bossio, Lead Soil Scientist at The Nature Conservancy and co-author of the paper published in Nature Sustainability. Authors of the paper conclude that ‘a clear focus on early wins and on continued collaboration will lay the ground for gains in soil organic carbon at scale within an urgent timeframe.’
Under the UN Climate Convention (UNFCCC) only eight countries include targets for soil organic carbon within their intended mitigation options – (Armenia, Burkina Faso, China, Japan, Malawi, Namibia, Uruguay and Zambia). That said, a few have policies that support stronger action, ranging from Canada, which recognizes the potential of soil organic carbon under conserved forests and wetlands, to Bhutan, with its sustainable soil policy.
Pioneering initiatives – both regulatory and voluntary – at national and sub-national levels, also provide evidence of economic viability and rapid results at the local level. Australia and California are examples of early adopters of market-based approaches to raising soil organic carbon. Australia’s Carbon Farming Initiative, a legislated voluntary offsets scheme implemented by the Emission Reduction Fund, has awarded contracts with an approximate value of A$200 million to landholders and farmers to earn carbon credits from soil organic carbon projects on degraded land, supporting a wide range of activities from rotational grazing to reduced tillage.
In the private sector, a growing number of companies are also including soil organic carbon within their set of options to build resilience and long-term profitability of agricultural value chains. Danone, Mars, Bayer, Coca Cola, Fonterra, Diageo and Olam are multinational examples.
“We need a new mindset,” said Deborah Bossio. “We need to give up on the idea that it’s all too hard. To combat climate change and to produce healthy diets, we need every tool in the toolbox. We might not think about soil all the time, but boy we notice it when it’s gone.”
Julia K. Green, Sonia I. Seneviratne, Alexis M. Berg, Kirsten L. Findell, Stefan Hagemann, David M. Lawrence & Pierre Gentine. Large influence of soil moisture on long-term terrestrial carbon uptake. Nature, 2019 DOI: 10.1038/s41586-018-0848-x
A new study confirms the urgency to tackle climate change. While it’s known that extreme weather events can affect the year-to-year variability in carbon uptake, and some researchers have suggested that there may be longer-term effects, this study is the first to actually quantify the effects through the 21st century and demonstrates that wetter-than-normal years do not compensate for losses in carbon uptake during dryer-than-normal years, caused by events such as droughts or heatwaves.
…Anthropogenic emissions of CO2 — emissions caused by human activities — are increasing the concentration of CO2 in the Earth’s atmosphere and producing unnatural changes to the planet’s climate system. The effects of these emissions on global warming are only being partially abated by the land and ocean. Currently, the ocean and terrestrial biosphere (forests, savannas, etc.) are absorbing about 50% of these releases — explaining the bleaching of coral reefs and acidification of the ocean, as well as the increase of carbon storage in our forests.
“It is unclear, however, whether the land can continue to uptake anthropogenic emissions at the current rates,” says Pierre Gentine…
Marc G. Kramer, Oliver A. Chadwick. Climate-driven thresholds in reactive mineral retention of soil carbon at the global scale. Nature Climate Change, 2018; 8 (12): 1104 DOI: 10.1038/s41558-018-0341-4
One answer to our greenhouse gas challenges may be right under our feet: Soil scientists have found that minerals in soil can hold on to a significant amount of carbon pulled from the atmosphere. It’s a mechanism that could potentially be exploited as the world tries to shift its carbon economy. …
… Wetter climates are more conducive to formation of minerals that are effective at storing carbon, therefore much of the Earth’s estimated 600 billion metric tons of soil-bound carbon is found in the wet forests and tropical zones. Arid places, meanwhile, tend to have a “negative water balance” and can thus store far less organic carbon. According to Chadwick, the findings suggest that even a small, strategic change in the water balance could drive greater carbon storage.
… There is still a lot to investigate and several hurdles to overcome as soil scientists everywhere consider ways to tip the balance of the Earth’s soil from carbon source to carbon sink, but according to these researchers, understanding this relatively little-known but highly significant carbon storage pathway is a start.
Rebecca K James et al. Maintaining Tropical Beaches with Seagrass and Algae: A Promising Alternative to Engineering Solutions. BioScience, 2019; DOI: 10.1093/biosci/biy154
Seagrass beds are so effective in protecting tropical beaches from erosion, that they can reduce the need for regular, expensive beach nourishments that are used now. In a recent article in the journal BioScience, biologists and engineers from The Netherlands and Mexico describe experiments and field observations around the Caribbean Sea. “A foreshore with both healthy seagrass beds as well as calcifying algae, is a resilient and sustainable option in coastal defense,” says lead author Rebecca James, PhD-candidate at the University of Groningen and the Royal Dutch Institute for Sea Research (NIOZ), The Netherlands. “Because of erosion, the economic value of Caribbean beaches literally drains into the sea….