President Obama made addressing climate change a prominent policy vow during his second Inaugural Address, as NASA validates that Earth's long-term global-warming trend continues.
Scientists at NASA's Goddard Institute for Space Studies (GISS) say 2012 was the ninth warmest year since 1880, continuing a long-term trend of rising global temperatures. The 10 warmest years in the 132-year record have occurred since 1998. The last year that was cooler than average was 1976.
Scientists emphasize that weather patterns cause fluctuations in average temperatures from year to year, but the continued increase in greenhouse gas levels in the atmosphere assures that there will be a long-term rise in global temperatures. Each individual year will not necessarily be warmer than the previous year, but scientists expect each decade to be warmer than the previous decade.
One more year of numbers isn't in itself significant, said GISS climatologist Gavin Schmidt. What matters is this decade is warmer than the last decade, and that decade was warmer than the decade before. The planet is warming. The reason it's warming is because we are pumping increasing amounts of carbon dioxide into the atmosphere.
Image courtesy of NASA.