How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

IPCC AR4 Projections of Indian Summer Monsoon-ENSO Links
Roxy, M., Patil, N., Ashok, K. and Aparna, K. 2013. Revisiting the Indian summer monsoon-ENSO links in the IPCC AR4 projections: A cautionary outlook. Global and Planetary Change: 10.1016/j.gloplacha.2013.02.003.

The authors note that recent studies point out the existence of a new phenomenon, referred to as the El Niņo Modoki, which is characterized by a warm sea surface temperature (SST) anomaly in the central equatorial Pacific and a cold SST anomaly in the western and eastern Pacific, with some arguing that "the increasing frequency of the El Niņo Modoki in recent decades is due to global warming." And they say that in this context it is imperative to examine the changing teleconnection between ENSO/Modoki and the Indian summer monsoon.

What was done
In the words of Roxy et al., "climate change experiments under the fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), namely the twentieth century simulations (20C3M) and Special Report on Emissions Scenarios (SRES) A1B, are revisited to study whether these models can reproduce the ENSO and ENSO Modoki patterns," as well as "their teleconnections with the Indian summer monsoon, and also the implications for the future."

What was learned
The four researchers from India report that (1) "only ~1/4th of the models from 20C3M capture either ENSO or ENSO Modoki patterns in June, July, August and September," that (2) "of this 1/4th, only two models simulate both ENSO and ENSO Modoki patterns as important modes," and that (3) "out of these two, only one model simulates both ENSO and ENSO Modoki as important modes during both summer and winter." In addition, they say that the two models that demonstrate ENSO Modoki, as well as ENSO associated variance in both 20C3M and SRES A1B, project just the opposite types of impacts of SRES A1B.

What it means
Quoting Roxy et al., all of these findings are indicative of "the challenges associated with the limitations of the models in reproducing the variability of the monsoons and ENSO flavors, not to speak of failing in capturing the potential impacts of global warming as they are expected to." But wait. There is a silver lining in these cloudy results; for as they conclude in the final sentence of their abstract, "more research in improving the current day simulations, improving model capacity to simulate better by improving the Green House Gases and aerosols in the models are some of the important and immediate steps that are necessary."

And so the saga of global climate models never quite arriving at an adequate level of reliability continues, as does the never-ending stream of money that is poured into the endeavor by cash-strapped governments around the world.

Reviewed 5 June 2013