ONE TOWN SQUARE: at the intersection of peak oil, climate change, and land use

Two new studies warn that damage from climate change will last thousands of years.

A study led by NOAA senior scientist Susan Solomon shows that changes in surface temperature, rainfall, and sea level are largely irreversible for more than 1,000 years after carbon dioxide (CO₂) emissions are completely stopped. The most important finding is that there will be “irreversible precipitation changes” (that is, drought) in the U.S. Southwest, Southeast Asia, Eastern South America, Western Australia, Southern Europe, Southern Africa, and northern Africa.

My beloved South of France really takes it on the chin.

The findings appear during the week of January 26 in the Proceedings of the National Academy of Sciences. While the press release is available for free, the study itself isn’t. Joseph Romm at Climate Progress has posted an excerpt:

…the climate change that is taking place because of increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop…. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450-600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the ”dust bowl” era and inexorable sea level rise.

Another new study finds global warming could cause severe ocean oxygen depletion that would leave huge areas of the ocean devoid of fish and seafood. The authors warn that substantial reductions in fossil-fuel use over the next few generations are needed if extensive ocean oxygen depletion for thousands of years is to be avoided.

Continued global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide produced by fossil-fuel burning from the atmosphere. A 100,000-year simulation indicates that these “dead zones” could endure for thousands of years.

The study, titled “Long-term ocean oxygen depletion in response to carbon dioxide emissions from fossil fuels“, is published in the journal Nature Geoscience. The full text is behind a paywall. The  abstract is below the fold:

Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere. Future warming may have large global impacts including ocean oxygen depletion and associated adverse effects on marine life, such as more frequent mortality events, but long, comprehensive simulations of these impacts are currently not available. Here we project global change over the next 100,000 years using a low-resolution Earth system model, and find severe, long-term ocean oxygen depletion, as well as a great expansion of ocean oxygen-minimum zones for scenarios with high emissions or high climate sensitivity. We find that climate feedbacks within the Earth system amplify the strength and duration of global warming, ocean heating and oxygen depletion. Decreased oxygen solubility from surface-layer warming accounts for most of the enhanced oxygen depletion in the upper 500 m of the ocean. Possible weakening of ocean overturning and convection lead to further oxygen depletion, also in the deep ocean. We conclude that substantial reductions in fossil-fuel use over the next few generations are needed if extensive ocean oxygen depletion for thousands of years is to be avoided.