Climate scientists at NASA have ranked 2012 as the ninth-warmest year since 1880, when annual temperatures were first recorded. Their findings also show that the ten hottest years over this 132-year period have all occurred since 1998, adding to a growing body of evidence that the world's temperature is rising. The report, published by the Goddard Institute for Space Studies (GISS), comes just a few days after the US government declared 2012 as the hottest year on record within the lower 48 states.
Last year, the world saw an average temperature of 58.3 degrees Fahrenheit, a full degree higher than NASA's mid-20th century baseline average. Since 1880, this average has risen by 1.4 degrees Fahrenheit, with much of this increase coming within the last four decades.
"What matters is this decade is warmer than the last decade, and that decade was warmer than the decade before."
NASA was unequivocal in explaining this trend, citing increased carbon dioxide emissions as the primary driver behind rising temperatures. And while scientists acknowledge that we may see fluctuations over the coming years, they maintain that overarching trends point to an increasingly hot planet. According to NASA, the last time the Earth saw below average temperatures was back in 1976.
"One more year of numbers isn’t in itself significant," GISS climatologist Gavin Schmidt said in a statement. "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."
The severity of these changes is perhaps best contextualized with a computer simulation that NASA released this week (embedded below). According to NASA GISS director James E. Hansen, these trends should be taken with a sense of urgency, given the impact such extreme climate change can have on the environment and human life.
"The climate dice are now loaded," Hansen said. "Some seasons still will be cooler than the long-term average, but the perceptive person should notice that the frequency of unusually warm extremes is increasing. It is the extremes that have the most impact on people and other life on the planet."