Leading IPCC Scientist Admits Climate Risk Has Been Underestimated
by Andrew Glikson
16 February 2009
Since 1990 the four reports by the Intergovernment Panel on Climate Change (IPCC), established by the United Nationa in 1988, were criticized for being watered down by government officials, and for underestimating the effects of carbon cycle feedbacks, the dynamics of ice sheet melt, methane emissions, and the rate of temperature and sea level rise, currently tracking near the top of IPCC projections (Rahmstorf et al., 2007) http://www.sciencemag.org/cgi/content/abstract/1136843v1.
Now a leading IPCC scientist, Chris Field (Stanford University and the Carnegie Institution for Science), points out the fourth assessment report of the IPCC has underestimated the potential severity of global warming over the next 100 years. http://www.eurekalert.org/pub_releases/2009-02/su-ccl021009.php
Field is a lead author of the IPCC fourth assessment (AR4), which concluded that the Earth's temperature is likely to increase by 1.1 to 6.4 degrees C by 2100, depending on the extent of greenhouse gas emissions in coming decades. Field will oversee the writing and editing of Working Group 2 Report for the IPCC fifth assessment due in 2014. According to Filed the Report will include more severe warnings than previous reports.
At the annual meeting of the American Association for the Advancement of Science (AAAS) in Chicago, 14.2.2009, in a symposium titled "What Is New and Surprising Since the IPCC Fourth Assessment?" Field stated several recent climate models have estimated that the loss of tropical rainforests to wildfires, deforestation and other causes could increase the concentration of carbon dioxide in the atmosphere from 10 to 100 parts per million by the end of the 21st century. "We are basically looking now at a future climate that is beyond anything that we've considered seriously in climate policy".
"There is a real risk that human-caused climate change will accelerate the release of carbon dioxide from forest and tundra ecosystems, which have been storing a lot of carbon for thousands of years" ... "We don't want to cross a critical threshold where this massive release of carbon starts to run on autopilot."
Between 2000 and 2007 emissions increased at a faster rate than predicted, primarily by China and India, where electric power generation is mostly based on coal. This trend is likely to continue if more developing countries turn to coal and other carbon-intensive fuels to meet their energy needs. "If we're going to continue re-carbonizing the energy system, we're going to have big CO2 emissions in the future" ... "Without aggressive attention, societies will continue to focus on the energy sources that are cheapest, and that means coal" ... "Predictions of a decrease in carbon emissions had also been too optimistic, he said, as no part of the world has seen such a decline between 2000 and 2008." ... "As a result, the impacts of climate change will probably be more serious and diverse than those described in the fourth assessment."... "It is increasingly clear that as you produce a warmer world, lots of forested areas that had been acting as carbon sinks could be converted to carbon sources..
Carbon feedbacks from tropical forests and Arctic tundra melting, releasing billions of tons of greenhouse gas, could spiral out of control, rendering IPCC estimates conservative. That could raise temperatures even more and create a vicious cycle that could spiral out of control by the end of the century.
Fields concerns are relevant to forest fires: "Tropical forests are essentially inflammable," ... "You couldn't get a fire to burn there if you tried. But if they dry out just a little bit, the result can be very large and destructive wildfires."
With implications to the Victorian fires.
Field states the next IPCC Report will indicate that, without effective action, climate change is going to be larger and more difficult to deal with, adding We really have very little time."
Communicated by Andrew Glikson