Hexbyte Glen Cove Breaching tipping points would increase economic costs of climate change impacts thumbnail

Hexbyte Glen Cove Breaching tipping points would increase economic costs of climate change impacts

Hexbyte Glen Cove

Credit: CC0 Public Domain

Exceeding tipping points in the climate system could lead to a measurable increase in the economic impacts of climate change, according to a new paper published in the journal Proceedings of the National Academy of Sciences.

Researchers from the London School of Economics and Political Science, University of Delaware and New York University have created a new model to estimate the economic impacts of climate tipping points, such as disintegration of the Greenland Ice Sheet.

The paper on ‘Economic impacts of tipping points in the ‘ was written by Simon Dietz (London School of Economics and Political Science), James Rising (University of Delaware), Thomas Stoerk (London School of Economics and Political Science), and Gernot Wagner (New York University).

In the authors’ main scenario, the risks of these tipping points occurring increases the economic cost of damages we can expect from climate change by about 25 percent compared with previous projections.

However, the authors stress that the results for their main scenario could be conservative, and that tipping points could increase the risks of much greater damages. Their study finds that there is a 10 percent chance of the tipping points at least doubling the costs of impacts, and a 5 percent chance of them tripling costs.

The authors considered eight tipping points that have been described in the scientific literature:

  • Thawing of permafrost, leading to carbon feedback resulting in additional and methane emissions, which flow back into the carbon dioxide and methane cycles.
  • Dissociation of ocean methane hydrates, resulting in additional , which flow back into the methane cycle.
  • Arctic sea ice loss (also known as ‘the surface albedo feedback’), resulting in changes in radiative forcing, which directly affects warming.
  • Dieback of the Amazon rainforest, releasing carbon dioxide, which flows back into the carbon dioxide cycle.
  • Disintegration of the Greenland Ice Sheet, increasing sea-level rise.
  • Disintegration of the West Antarctic Ice Sheet, increasing sea-level rise.
  • Slowdown of the Atlantic Meridional Overturning Circulation, modulating the relationship between global mean surface temperature and national mean surface temperature.
  • Variability of the Indian summer monsoon, directly affecting GDP per capita in India.

The study found that economic losses associated with the tipping points would occur almost everywhere in the world. The dissociation of ocean methane hydrates and thawing permafrost would create the largest economic impacts.

The model includes national-level climate damages from rising temperatures and sea levels for 180 countries.

The authors emphasize that their estimate of the impacts are probably underestimates, but their model can be updated as more information about tipping points is discovered.

Professor Simon Dietz at the Department of Geography and Environment and the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, said that “climate scientists have long emphasized the importance of climate tipping points like thawing permafrost, ice sheet disintegration, and changes in atmospheric circulation. Yet, save for a few fragmented studies, climate economics has either ignored them, or represented them in highly stylised ways. We provide unified estimates of the economic impacts of all eight tipping points covered in the economic literature so far.”



More information:
James Rising et al, Economic impacts of tipping points in the climate system, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2103081118

Provided by
Grantham Research Institute on Climate Change and the Environment

Citation:
Breaching tipping points would increase economic costs of climate change impacts (2021, August 16)
retrieved 16 August 2021

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Hexbyte Glen Cove Cleaning up the Mississippi River thumbnail

Hexbyte Glen Cove Cleaning up the Mississippi River

Hexbyte Glen Cove

Mississippi River in fog. Credit: LSU

Louisiana State University College of the Coast & Environment Boyd Professor R. Eugene Turner reconstructed a 100-year record chronicling water quality trends in the lower Mississippi River by compiling water quality data collected from 1901 to 2019 by federal and state agencies as well as the New Orleans Sewerage and Water Board. The Mississippi River is the largest river in North America with about 30 million people living within its watershed. Turner focused on data that tracked the water’s acidity through pH levels and concentrations of bacteria, oxygen, lead and sulfate in this study published in Ambio, a journal of the Royal Swedish Academy of Sciences.

Rivers have historically been used as disposal sites worldwide. From the polluted Cuyahoga River in Cleveland, Ohio that caught fire to the Mississippi River where sewage was dumped resulting in increases in lead and decreases in oxygen, rivers were environmentally hazardous until the passage of the U.S. Clean Water Act in 1972. The Clean Water Act as well as the Clean Air Act, the Toxic Substances Control Act and others established a federal structure to reduce pollutant discharges into the environment and gave the Environmental Protection Agency the authority to restrict the amounts and uses of certain toxic chemicals such as lead. Turner’s study assesses changes in quality before and after the Clean Water Act and Clean Air Act went into effect. The water quality data he compiled were collected from four locations on the southern end of the Mississippi River at St. Francisville, Plaquemine, two locations in New Orleans and at Belle Chasse, Louisiana.

His research found that after these were put into place, bacterial concentrations decreased by about 3 orders of magnitude, oxygen content increased, lead concentrations decreased and sulfate concentrations declined less dramatically. His research also found that as sulfur dioxide emissions peaked in 1965, the river’s pH dropped to a low of 5.8. In the U.S., natural water falls between 6.5 and 8.5 with 7.0 being neutral. However, as sulfur dioxide emissions declined in 2019, the pH of the river was restored to an average of 8.2.

“The promulgation and acceptance of the Clean Water Act and Clean Air Act demonstrates how public policy can change for the better and help everyone who is demonstrably ‘downstream’ in a world of cycling pollutants,” Turner said.

Consistent vigilance and monitoring are necessary to ensure water quality in the Mississippi River and northern Gulf of Mexico. Plastics fill oceans, pharmaceuticals are distributed in sewage and COVID-19 virus and other viruses spread in partially treated sewerage wastes from aging septic tanks, unconstrained wetland treatment systems with insufficient hydrologic controls and overloaded treatment systems.

New pollutants are added to the river each year, which will require monitoring and testing. Unfortunately, lead monitoring has stopped, but decades of sustained and effective efforts at a national scale created water quality improvements and are an example for addressing new and existing challenges, Turner said.



More information:
Turner, R.E. Declining bacteria, lead, and sulfate, and rising pH and oxygen in the lower Mississippi River. Ambio (2021). doi.org/10.1007/s13280-020-01499-2

Journal information:
AMBIO


Citation:
Cleaning up the Mississippi River (2021, February 8)
retrieved 9 February 2021
from https://phys.org/news/2021-02-mississippi-river.html

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