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John Walsh is one of the more prominent scientists studying global climate change in the 21^st century, but his work in the field began decades ago when the topic and the science rarely made headlines.

In a 2016 article, a colleague described Walsh’s early work in collecting data on the historic extent of Arctic and Antarctic sea ice, work that proved valuable for gauging today’s changes.

Walsh and another researcher hand-digitized information from shipping reports, aerial surveys and other sources, according to Florence Fetterer of the National Snow and Ice Data Center in Colorado.

“Walsh, along with Professor William Chapman from University of Illinois, used these various sources to make monthly grids in Arctic and Southern Ocean sea ice concentrations, covering the period 1901-1995,” Fetterer wrote. “These grids proved to be very popular among researchers — possibly because there were few alternatives.”

Walsh spent 30 years at the University of Illinois after earning his doctorate at the Massachusetts Institute of Technology and bachelor’s degree from Dartmouth College.

He came to ���Ϻ�����Ƶ in 2001 as the president’s professor of climate change. He is now chief scientist at ���Ϻ�����Ƶ’s International Arctic Research Center.

In 2007, Walsh was among the principal authors of the second volume of the Fourth Assessment Report from the Intergovernmental Panel on Climate Change. He led the polar regions chapter.

The assessment drew enormous media attention. Later that year, the Nobel Peace Prize went most famously to former U.S. Vice President Al Gore. But Gore shared the award with the IPCC, which was recognized for reports that “created an ever-broader informed consensus about the connection between human activities and global warming.” The World Meteorological Organization and the United Nations Environment Programme formed the IPCC in 1988.

Some researchers, including Walsh, said the final 2007 report, though full of dire predictions, had been watered down by governments seeking to downplay the need to reduce carbon emissions. “The science got hijacked by the political bureaucrats at the late stage of the game," Walsh told the Los Angeles Times that year.

Walsh continues to conduct research, lecture and participate in climate assessments. He was a lead author in the National Climate Assessment issued by the U.S. Global Change Research Program in 2013.

More online about John Walsh:

• A 2007 ���Ϻ�����Ƶ news release about his authorship of the polar regions chapter in the second volume of the Fourth Assessment Report from the Intergovernmental Panel on Climate Change

• quoting his comments on the process leading up to release of the IPCC report

• A 2009 ���Ϻ�����Ƶ news release about his reception of the Emil Usibelli Award for research

• A 2008 ���Ϻ�����Ƶ news release about his selection as a fellow of the American Association for the Advancement of Science

• describing some of his early work on documenting historical sea ice extent