Climate change tipping point could be coming sooner — Vegetation and soil may not be able to sequester as much carbon due to variability in soil moisture

A net gain of carbon on the land surface, would actually be almost twice as high if it weren’t for the variability in soil moisture

Columbia University School of Engineering and Applied Science Read full ScienceDaily article here

  • 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 uptakeNature, 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…

Desalination plants produce more waste brine than than previously thought

There’s enough wastewater from the world’s facilities to cover Florida a foot deep—here’s why that’s a potential problem.

By Tik Root Read full National Geographic article here

As clean freshwater has become scarcer around the world—especially in arid regions such as the Middle East and North Africa—those countries that can afford it have increasingly turned to desalination. That energy-intensive process extracts salt from sea (or other saline) water, transforming it into water that’s fit for human consumption. There are now nearly 16,000 desalination plants either active or under construction across the globe.

“[But] they don’t just produce desalinated water,” explains Manzoor Qadir, a researcher at the United Nations University in Canada. “They also produce brine.” Brine is the concentrated salt water that’s left after desalination. But Qadir says, “there is no comprehensive assessment” of how much is being produced. …Qadir’s team analyzed available literature as well as a database of roughly 20,000 desalination plants (including some that are no longer active)….

The literature had long assumed a one-to-one ratio. But Qadir’s study found that the average desalination plant actually produced 1.5 times more brine than desalinated water—fifty percent more than previously thought. That translates to 51.8 billion cubic meters of brine each year, which Qadir says is enough to cover all of Florida, a foot deep.

….Arguably best known [deleterious impact of desalination] is the copious amount of fossil fuels that are often used to power the plants, resulting in a significant amount of emissions. Most desalination plants work by reverse osmosis, meaning energy is needed to push water past a membrane at high pressure in order to separate the salt (learn more how it works). A typical plant takes an average of 10 to 13 kilowatt hours of energy per every thousand gallons processed. That energy use adds to the cost of the process. A recent desalination plant in California cost a billion dollars, and now provides about ten percent of the drinking water of the county of San Diego. The cost, and environmental impacts, of this overall industry have spurred researchers to look for alternatives, including developing more efficient separation membranes and desalination units that can be powered by solar energy. (Learn more about these emerging efforts.)

On the intake side, Burt says that small organisms such as fish larvae and coral can get sucked into a plant. But the greater risk comes at the other end of the process, when the brine is put back into the ocean (where the majority of desalination is done)…..

“Brine will be substantially higher in salinity than normal oceanic water,” he said. “The brine discharge is also warm.” Those conditions, he says, can make it more difficult for marine life in the immediate vicinity of the discharge to survive or thrive.

What Burt is more concerned about, however, are the chemicals that are often in the brine. Qadir’s study points to copper and chlorine as particularly troublesome compounds. …

Understanding of water resilience in the Anthropocene

Read Journal of Hydrology article here, MalinFalkenmarka, LanWang-Erlandssonab

JohanRockströmachttps://doi.org/10.1016/j.hydroa.2018.100009

HIGHLIGHTS: •Ample evidence of water related regime shifts in ecological and social systems.•Eight water functions provide social-ecological resilience in the Anthropocene.•Water flows and states often serve several water functions at once.•Feedbacks and roles of water at the core of the water resilience framework.•Water functions are essential for Earth system resilience and sustainable development.

Abstract

Water is indispensable for Earth resilience and sustainable development. The capacity of social-ecological systems to deal with shocks, adapting to changing conditions and transforming in situations of crisis are fundamentally dependent on the functions of water to e.g., regulate the Earth’s climate, support biomass production, and supply water resources for human societies. However, massive, inter-connected, human interference involving climate forcing, water withdrawal, dam constructions, and land-use change have significantly disturbed these water functions and induced regime shifts in social-ecological systems. In many cases, changes in core water functions have pushed systems beyond tipping points and led to fundamental shifts in system feedback. Examples of such transgressions, where water has played a critical role, are collapse of aquatic systems beyond water quality and quantity thresholds, desertification due to soil and ecosystem degradation, and tropical forest dieback associated with self-amplifying moisture and carbon feedbacks. Here, we aggregate the volumes and flows of water involved in water functions globally, and review the evidence of freshwater related linear collapse and non-linear tipping points in ecological and social systems through the lens of resilience theory. Based on the literature review, we synthesize the role of water in mediating different types of ecosystem regime shifts, and generalize the process by which life support systems are at risk of collapsing due to loss of water functions. We conclude that water plays a fundamental role in providing social-ecological resilience, and suggest that further research is needed to understand how the erosion of water resilience at local and regional scale may potentially interact, cascade, or amplify through the complex, globally hyper-connected networks of the Anthropocene.

Carbon Market Incentives to Conserve, Restore and Enhance Soil Carbon

September 2018  Read full report here and summary here

Soils rich in organic carbon are associated with enhanced agricultural productivity, water cycling, biodiversity and climate change adaptation and mitigation. But despite the important role they can play in fighting climate change, to date soils have largely been missing from carbon markets.

There are signs that the future may be more promising. This study assesses the specific situation of soil carbon—its position in climate policymaking, the specific challenges, and the opportunities for intervention. It does so to explore to what extent carbon project finance tools can help advance the ability of soil carbon to make a meaningful contribution to climate change mitigation, providing multiple co-benefits. By taking the voluntary market as the lens, it also serves to inform the wider fate and utility of land sector carbon projects within the evolving political framework of the Paris Agreement.

Deborah Bossio, TNC, was a consultant on this project.

von Unger, M. & Emmer, I. (2018). Carbon Market Incentives to Conserve, Restore and Enhance Soil Carbon. Silvestrum and The Nature Conservancy, Arlington, VA, USA