Established by the United Nations in 1988, the IPCC brings together hundreds of experts from around the world to assess the science and policy implications of climate change. In 2007, the IPCC and Al Gore were awarded the Nobel Peace Prize. Field was among 25 IPCC scientists who attended the award ceremony in
. Oslo, Norway
Since 1990, the IPCC has published four comprehensive assessment reports on human-induced climate change. Field was a coordinating lead author of the fourth assessment, Climate Change 2007, which concluded that the Earth's temperature is likely to increase 2 to 11.5 degrees Fahrenheit (1.1 to 6.4 degrees Celsius) by 2100, depending on how many tons of greenhouse gases are released into the atmosphere in coming decades.
But recent climate studies suggest that the fourth assessment report underestimated the potential severity of global warming over the next 100 years. "We now have data showing that from 2000 to 2007, greenhouse gas emissions increased far more rapidly than we expected, primarily because developing countries, like China and India, saw a huge upsurge in electric power generation, almost all of it based on coal," Field said.
This trend is likely to continue, he added, 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," he said. "As a result, the impacts of climate change will probably be more serious and diverse than those described in the fourth assessment."
IPCC assessment reports are organized into three working groups. In September 2008, Field was elected co-chair of Working Group 2, which is charged with assessing the impacts of climate change on social, economic and natural systems. One of his major responsibilities is to oversee the writing and editing of the "Working Group 2 Report" for the IPCC fifth assessment, which will be published in 2014.
"In the fourth assessment, we looked at a very conservative range of climate outcomes," Field said. "The fifth assessment should include futures with a lot more warming."