According to new data, 2012 was a chart-topping year for the United States – but not in a good way.

The National Oceanic and Atmospheric Administration’s (NOAA’s) National Climate Data Center (NCDC) recently declared 2012 to be the hottest year on record for the contiguous United States. This year shattered the previous record temperature, set in 1998, by 1.0°F. The year was also marked by 11 extreme weather events that each caused more than $1 billion of damages.

In a year that brought the United States record-breaking wildfire activity, an ongoing drought, and Hurricane Sandy, perhaps these announcements aren’t surprising. But they are troubling: Record-breaking temperatures and the rising frequency of extreme weather events illustrate that climate change is happening. These trends are expected to worsen the longer we delay serious action to reduce carbon pollution.

Take a look at a few of the figures illustrating the intensity and impacts of 2012’s extreme weather and climate events:

Temperature Records

• 356: Number of all-time temperature highs tied or broken in the United States in 2012
  
• 5-to-1: The ratio of daily record highs to daily record lows in 2012 – the largest ratio of this kind since record-keeping began in 1895
  
• 55.3°F: The average temperature in the United States in 2012 (3.3°F higher than the 20th Century average)
  
• 76.9°F: Average temperature in July 2012, the hottest month ever recorded in the contiguous United States (3.6°F above the historical average)
  
• 19: Number of states experiencing a record warm year

Impacts

• 99.1 million: Number of people experiencing 10 or more days that exceeded 100°F in temperature – more than one-third of America’s total population
  
• 65.5 percent: Area of continental United States experiencing drought during its peak in September
  
• 11: Number of estimated disasters in 2012 that caused more than $1 billion of losses each.
  
• 8.5 million: Total number of homes that lost power during Hurricane Sandy
  
• 300,000: Number of acres burned during the largest wildfire in New Mexico’s recorded history
  
• 350: Number of homes destroyed by Colorado’s Waldo Canyon wildfire, the state’s most destructive wildfire in history
  
• 19: Number of named storms and hurricanes in 2012 – an above-average amount of tropical cyclone activity

Global Climate Change

On January 11, the National Climate Assessment and Development Advisory Committee will meet to consider approval of the first public draft of the Third National Climate Assessment (NCA) report. The previous NCA, published in 2009, concluded that many types of extreme weather and climate events are on the rise in the U.S., and that rising carbon pollution will very likely cause a continuation of these troubling trends in the future. All indications suggest that the 2013 NCA will reach the same conclusion.

Of course, what’s happening in the United States is a reflection of a warming planet. The world has experienced 333 consecutive months of global temperatures above the 20th-century average, as of November 2012 (December data is still forthcoming). Research shows that over the past 20 years, global sea levels rose 60 percent faster than what the Intergovernmental Panel on Climate Change (IPCC) had previously projected. And this past year, Arctic sea ice reached record lows, while the Greenland ice sheet experienced its largest extent of ice melt in satellite-recorded history (since 1979).

The connection between this long-term warming and climate change is well-established. And there’s increasing evidence linking individual events like heat waves and extreme weather occurrences to global warming. The IPCC released a study in March linking climate change to changes in extreme weather and climate events – like heat waves and heavy precipitation – in many regions over the past 50 years. Scientists at NOAA, the U.K.’s Met office, and other research institutions linked individual extreme events – like the 2011 Texas drought – to climate change. And renowned climate scientist James Hansen released a report indicating that extreme summer heat waves are much more likely to occur today than 20 years ago due to human-induced climate change.

What Do We Do?

All levels of government must recognize the reality of climate change and begin adaptation planning now to protect vulnerable populations and critical infrastructure from the damaging effects of climate change.

Equally important is the urgent need to begin significantly reducing carbon pollution. Until global emissions levels decline significantly, the atmospheric concentration of greenhouse gases will continue to rise. And unless we manage to stabilize the atmospheric concentrations at a sustainable level, communities, businesses, and the environment will be faced with managing the unmanageable.

With President Obama about to enter his second term, the United States has an opportunity to take a leadership role in this area. His administration has made some progress in curbing greenhouse gas emissions, most notably with new vehicle emissions standards and proposed regulations for new power plants. But the country has to go further in meeting its commitment to reduce overall emissions by 17 percent by 2020 and much greater reductions in the decades ahead. The best place to start is with meaningful new emissions standards for existing power plants.

The time for action is now. Without serious progress, we’re poised to continue breaking records – and experiencing the disastrous impacts that go with them.