It Was Very, Very Hot But….

…What Are the Larger Environmental and Political Trends?

Last July was the hottest month on record (at the time), according to the U.S. National Oceanic and Atmospheric Administration. More specifically was 1.57 degrees F above the 20th-century average.

But a single data point does not a trend make. What does the larger picture look like?

First, July was the hottest month in a hot year. In fact, it was the 15th month in a row to break a monthly heat record.

Second, it comes after the hottest year on record. The graph below illustrates the years that have given us the ten highest temperatures on record (there are actually 16 years on the graph because some years were tied).

hottest years

Some critics of the data argue that these temperatures are not so unusual if we look beyond the era of recorded metrics and into temperatures of the last 10,000 years, as estimated by scientific methods such as ice core drilling.

However, an article published in Science contains a 11,000-year temperature reconstruction based on the available scientific data. It indicates that global average temperatures increased after the end of the last ice age and then leveled off from about 7550 and 3550 BC. From there, temperatures dropped, bottoming out somewhere between the Middle Ages and the 1800s. Then temperatures started to rise again, suddenly skyrocketing upwards in latter part of the 20th century. Today’s temperatures are, according to this data, higher than they’ve been for the last 11,300 years, as can be seen in the graph below.



Source:  From NOAA, which adapted the image from Figure 1(b) in Marcott et al.

So, the long-term trends suggest that it’s considerably hotter now than at any other time over the last eleven millennia.

The debate over the causes of these trends continues, though a majority of the world’s climate scientists believe these trends are linked to carbon emissions from fossil fuels. Trends in carbon emissions can be seen in the graph below, which is based on data from the U.S. Department of Energy.

carbon trajectory

The Political Divide

Pew Research reports that majorities of people in 40 nations view climate change as a serious problem, and a global median of a little over half (54%) consider it a very serious problem.

In the U.S., the issue has been polarizing. In fact, data aggregated from 2010 to 2015 by Gallup indicates that “partisanship rather than education is the main lens through which Americans view global warming and its effects, particularly for those who claim allegiance to one of the two major parties.”

Among college-educated Republicans, a considerable majority (66%) said that global warming was caused by natural changes in the environment, and 35% said global warming will never happen. In contrast, just 13% of Democrats said global warming was caused by natural changes and just 2% said global warming will never happen.

There are, however, signs that the political divide is narrowing. A survey released this year by Yale and George Mason universities found that 47% of conservative Republicans now believe that the climate is changing, a significant jump of 19 points since the mid-term elections of 2014. The poll also found that three quarters of all Republicans favor more research into renewable energies.

If the political gap does shrink, then the U.S. may begin to act more aggressively to regulate and discourage carbon emissions while providing incentives for low-carbon sources of energy. The state of the political gap, as much as the thermometer itself, will likely tell us a lot about the future.

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