"Facts are Stubborn Things ..."

In his defense of soldiers in the Boston Massacre trials, John Adams went on to say “… and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence.”

No matter what we may wish were happening, no matter what spin some may try to sell, the clear evidence of climate change continues to mount.

The U.S. National Oceanic and Atmospheric Administration (NOAA) has just released its annual report on the state of the climate, and the facts speak volumes about the pervasiveness and speed of actual climate change, not model projections. 

In addition to new and clear observations of continued ocean warming, rapid sea level rise, and losses in sea ice, glaciers and snow cover, State of the Climate in 2009 confirms that, globally, the 2000s were the warmest decade in NOAA’s temperature record (which began in the 1880s), with every single year of the decade warmer than the average temperature for the 1990s (see Figure 1). 

This is not just a blip in the record, as the 1990s were warmer than the 1980s, which were warmer than the 1970s. And in spite of the cold, snowy weather in the eastern U.S. this past winter, 2009 was one of the ten warmest years globally since at least 1880.


NOAA temperature record

Figure 1

The report also lists ten key indicators of global warming, all of which are changing in the direction that would be expected if the globe is warming. They include things like surface air temperature, sea surface temperature, ocean heat content, and sea level, all of which are increasing, and sea ice cover, snow cover, and glacier mass, all of which are decreasing. When averaged over the globe, these trends are only possible if the global temperature has been rising on average for several decades.

The strongest evidence for global average warming is the persistent rise in the amount of heat stored in the oceans (see Figure 2), since this is where 90 percent of the heat trapped by greenhouse gases is absorbed before it is released to the atmosphere.


Ocean heat content

Figure 2

Although State of the Climate in 2009 only covers observed climate change, the amount of heat in the oceans is a key indicator of future sea level rise and air temperature increases in the coming decades. The large amount of heat that has accumulated in the ocean since 1980 means that, even if we have a cool year here and there, the globe will continue to warm on average for several decades.

This warming that is in the system but yet to be realized in the atmosphere is often called “the warming in the pipeline.”  This is warming that we likely cannot avoid.  However, we need to avoid adding to the pipeline as much as possible by beginning to reduce our emissions of heat-trapping greenhouse gases as soon as possible. The longer we wait, the more future warming we load into the pipeline and the larger the risk to our environment and ultimately to our economy.

Read an accessible summary of State of the Climate in 2009 here.

Jay Gulledge is Senior Scientist and Director of the Science and Impacts Program