President Obama’s forceful call for climate action in his inaugural address came after a year when climate change was barely whispered in the presidential campaign but its effects were loud and clear here in the United States and around the world.
Globally , 2012 ranked as the 10th warmest since 1880. For the 36th year in a row, global temperatures were above the 20th century average. That’s where phrases like “the new normal” come from (although future years are expected to be significantly warmer than the recent past). Last year also saw large simultaneous droughts gripping important agricultural areas around the globe, including Russia, Ukraine, Kazakhstan, Northeast Brazil and central North America.
In the United States, last year was the hottest  in the lower 48 since we started keeping records in 1895. Nineteen states recorded their hottest year ever, mainly in the Plains and Northeast. Thirty-seven states experienced their warmest spring on record .
The record heat was accompanied by the worst drought  in decades. At one point during July, 61 percent of the continental U.S. was in moderate-to-exceptional drought. So far, the drought has persisted into 2013 without much improvement.
Impacts have included high corn and soybean prices , record low water levels in the Great Lakes  and near-record low water in the Mississippi River. The National Oceanic and Atmospheric Administration is now forecasting the Mississippi River to drop past 6 feet below normal  by mid-February, a level only an inch above the lowest on record, observed in 1940 near the end of the Dust Bowl.
And the extremes haven’t been confined to land. In the Arctic, sea ice shrank to a new record low , 18 percent below the previous record set in 2007. Ocean temperatures  off the Northeast coast were higher this summer than at any point in records dating back to 1854. This unusually warm water, plus higher sea levels, may have intensified the impact of Hurricane Sandy.
We’re already off to a rough start in 2013 with extreme heat in the Southern Hemisphere. The Australian Bureau of Meteorology had to add new colors  to their temperature map representing the intensity of the heat – as hot as 121 Fahrenheit. South Africa  saw the third hottest temperature it has ever recorded – 118 F.
Collectively these persistently high temperatures around the globe are warning signs of the road ahead. The challenges posed by drought and extreme heat offer important lessons to farmers, barge operators and crop insurers on how to adapt to a future where droughts and heat waves become more common and widespread. We must prepare our homes and businesses for rising sea levels, heavier precipitation, and other changes that are now unavoidable.
The broader lesson, however, is that we must reduce carbon emissions to a level where the future risks are manageable. Even as we work to increase the resilience of our infrastructure to the effects of climate change, we need stronger policies to encourage low-carbon innovation and investment and dramatically shrink our carbon output.