Jammin’ with the mid-Pliocene scene

November 26, 2008

Welcome to the mid-Pliocene.

“The mid-Pliocene experienced the most extreme warming over the past 3.3 million years. Global average temperatures were 2.5°C (4.5°F) greater than today and within the range projected for the 21st century by the Intergovernmental Panel on Climate Change…Since CO2 levels during the mid-Pliocene were only slightly higher than today’s levels, PRISM research suggests that a slight increase in our current CO2 level could have a large impact on temperature change. Research also shows warming of as much as 18°C, bringing temperatures from -2°C to 16°C, in the high latitudes of the North Atlantic and Arctic Oceans during the mid-Pliocene. Warming in the Pacific, similar to a present day El Niño, was a characteristic of the mid-Pliocene. Global sea surface and deep water temperatures were found to be warmer than those of today, impacting the ocean’s circulation system and climate. Data suggest the likely cause of mid-Pliocene warmth was a combination of several factors, including increased heat transport from equatorial regions to the poles and increased greenhouse gases.”

In other words, more evidence, this time from the Paleoclimatologists, that things aren’t looking great on the climate front. This research suggests some particularly shocking conclusions. C02 sensitivity – the ability of the Earth’s ecosystems to absorb greenhouse gases (GHGs) and the ways in which the climate responds to GHG forcing is a crucial thing to consider here.

Many climatologists have been talking about “tipping points” and “non-linear effects” in the weather system. The IPCC’s most recent assesment, which was bleak enough, didn’t consider these processes, which can see elements of the Earth’s biosphere jolting abruptly and massively to a different state. Think epochal releases of methane from SIberian peat bogs, or clathrates emanating from the oceans. Think the rainforest shrivelling up, the Arctic ice pack disappearing or the monsoon failing.

If this reconstruction from the mid-Pliocene is anything to go by, think all of these things. And consider being slightly afraid. Or doing something about it.

There is also great news on the ocean acidification front. Researchers from the University of Chicago are reporting that pH levels in temperate coastal waters – prime fishing spots in other words – have been “increased more than 10 times faster than had been predicted by climate change models and other studies.”

As Prof J. Timothy Wootton puts it, “This increase will have a severe impact on marine food webs and suggests that ocean acidification may be a more urgent issue than previously thought, at least in some areas of the ocean.”

Shellfish and corals will suffer, whilst algae will thrive – for a while. The areas of the globe that have supported vibrant fisheries for millenia, or even eons, will become gooey homogenous soups.

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