“The paper shows how natural climatic shifts stopped reef growth in the eastern Pacific for 2,500 years. The reef shutdown, which began 4,000 years ago…“
What were CO2 levels supposed to be then in definite pre-industrial times? The IPCC says 278 ppmv, right? I’ve seen a lot of coral in the GBR and it is thriving with levels nearing 400 ppmv. Corals didn’t fare so well in the ice age with levels down around the 200 ppmv mark. Corals evolved in the Ordovician with CO2 in the multiple thousand parts per million.
I’m seeing a pattern here – low CO2 bad, higher CO2, good.
Climate change drove coral reefs to a total ecosystem collapse lasting thousands of years, according to a paper published this week in Science. The paper shows how natural climatic shifts stopped reef growth in the eastern Pacific for 2,500 years. The reef shutdown, which began 4,000 years ago, corresponds to a period of dramatic swings in the El Niño–Southern Oscillation (ENSO). “As humans continue to pump greenhouse gases into the atmosphere, the climate is once again on the threshold of a new regime, with dire consequences for reef ecosystems unless we get control of climate change,” said coauthor Richard Aronson, a biology professor at Florida Institute of Technology.
Doctoral student Lauren Toth and Aronson, her adviser at Florida Tech, led the study of how past episodes of climate change influenced tropical reefs of the eastern Pacific. Toth, Aronson and a multi-institutional research team drove 17-foot, small-bore aluminum pipes deep into the dead frameworks of coral reefs along the Pacific coast of Panama and pulled out cross-sections of the reefs. By analyzing the corals in the cores, they were able to reconstruct the history of the reefs over the past 6,000 years.
“We were shocked to find that 2,500 years of reef growth were missing from the frameworks,” said Toth. “That gap represents the collapse of reef ecosystems for 40 percent of their total history.” When Toth and Aronson examined reef records from other studies across the Pacific, they discovered the same gap in reefs as far away as Australia and Japan.
ISTR that one of the historic data sets of CO2 measurements dusted off by the late Ernst-Georg Beck included those of the Atlantic traverses of a survey ship. One which showed the uneven distribution of CO2 near the surface; with a peak in the tropics in excess of 440 ppm (in the 1920′s) and the lows further away from the equator.