Climate change to blame for warmer weather in Delaware, worldwide

Maddy Lauria
The News Journal

Above-average temperatures are becoming the new normal around the globe, and Delaware is no exception.

That doesn’t mean the First State will turn into a desert or be underwater overnight. But it does mean small, long-term temperature changes could impact farming, diseases, pests and the resilience of beaches and the tourism industry they support.

“The warming surface of the earth – both ocean and land – means that certain parts of our biodiversity are more at risk,” said John Byrne, director of the University of Delaware’s Center for Energy and Environmental Policy. “For societies, we’re facing things like sea level rise, which is the result of a warming surface, and it means that certain diseases that prosper in warmth will become more pronounced. Agriculture may face benefits, and may also face serious decline. And in the everyday life of you and I, we are going to face problems with doing the things we normally do.”

Temperatures continue to break records worldwide, with 2017 now ranked as the second warmest year on record, according to NASA. NOAA's data indicates 2017 was the third warmest year.

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Scientists with the National Aeronautics and Space Administration and the National Oceanic and Atmospheric Administration announced last week that 2017 has ranked as one of the warmest years seen worldwide since record-keeping began in the late 1800s.

In Delaware, preliminary data indicate that 2017 will rank as the second warmest year on record with temperatures that were 3.6 degrees above the mean average from 1895 to 2017, said Delaware State Climatologist Dan Leathers. Looking only at the average from 1981 to 2010, 2017 was about 2 degrees warmer than normal.

Delaware has seen an increase of about 0.2 degrees per decade since record-keeping began in 1895, which has translated to a longer growing season as the first and last frosts of the year are delayed.

The Delaware Center for the Inland Bays estimated in its 2016 annual report that Delaware’s growing season, as measured in Lewes, has expanded by about 45 days.  

Climate change is ushering in more extreme weather, with rising probabilities for hardships such as the drought of 2008, which ravaged corn crops in Delaware. Days with 100 degree or higher temperatures could rise to a dangerous 15 to 30 days a year, compared with less than once annually during the past century.

The only hotter year seen in the First State was in 2012, which saw an average nearly 4 degrees above normal mean temperature of 54.9.

NASA and NOAA disagree on whether 2017 ranked as No. 2 or No. 3 because of differing methods to analyze global temperatures – partially because they use different baseline time periods. However, both agencies agree that the five warmest years on record have all occurred since 2010.

Globally, temperatures were 1.62 degrees warmer than the mean average from 1951 to 1980. NASA said only 2016 ranked warmer, while NOAA said both 2016 and 2015 saw higher average temperatures than 2017.

NOAA looks at a 138-year-long climate record for rankings, and found 2017 was 1.51 degrees above the 20th century average. Scientists also noted 2017 was not an El Niño year, in which warmer temperatures would be expected.

This also marks 41 consecutive years with global land and ocean temperatures above the 20th century average, NOAA found.

“The recent findings from NOAA are an indicator that those trends are as predicted and we are seeing overall a warming globe,” said Byrne.

The burning of fossil fuels is to blame for the changing climate, he added.

“About 80 percent of what human activity contributes to greenhouse gas emissions comes from our energy sector and it’s from the burning of fossil fuels,” he said.

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If no changes are made to the world’s use of fossil fuels and greenhouse gas emissions, scientist believe this warming trend will inevitably continue.

In Delaware, that could mean yearly average temperatures of nearly 70 degrees by 2100, according to the University of Delaware’s Climate Projections Portal. The current average, as measured by mean temperatures from 1981 to 2010, is 55.4 degrees.

An abnormally warm February, April and October helped drive up Delaware’s 2017 average, Leathers said.

October 2017 was very warm at about 5.5 degrees above normal, making it the second warmest October in Delaware since 1895.

But February and April were even more abnormal, Leathers said. Temperatures in February were 7.6 degrees above normal, while April was 6.3 degrees warmer than usual.

“All three of the months above were in the top three warmest for their respective months since 1895,” Leathers said. “In addition, June and July were both in the Top 15 warmest since 1895 as well.”

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Overall, Delaware has seen temperatures rise by 0.2 degrees per decade, with a decrease in days below 20 degrees and an increase of hotter days over 75 degrees. As for precipitation, local climate scientists have seen no significant changes except for an increase of rainfall during the fall.

“When we have a cold snap like we did here in January, people might tend to reflect on climate change and ask if it is really happening or not,” said Beth Chajes, Delaware state coordinator for the Citizens Climate Lobby. “If they look at what’s happening between cold snaps, you get a sense of that background temperature and that’s definitely warmer.”

From the end of December through the first week of January, Delaware saw one of its longest cold snaps in decades. By mid-January, below-freezing temperatures had switched to unseasonably warm weather. Forecasts show Delawareans will see high temperatures up to 60 degrees this week.

“Some scientists like to call is global weirding instead of global warming,” Chajes said. “It’s not constant warming all the time. Sometimes it’s changes in extremes of weather and things like sea level rise.”

Delaware studies have estimated if the temperature continues to increase at the same rate, up to 11 percent of Delaware’s land mass could be underwater by 2100, the First State will feel more like Georgia than Delaware, health impacts from asthma and ozone alert days will increase and farmers will have to adjust their growing seasons and deal with more warm-weather pests and diseases.

“Even if people aren’t living on the beach and their property isn’t going to be affected by sea level rise, it’s very likely they or someone in their family is going to suffer some health effects,” Chajes said. “And all these things have a cost.”

To learn more about climate change in Delaware, go to de.gov/climatechange.

Contact reporter Maddy Lauria at (302) 345-0608, mlauria@delawareonline.com or on Twitter @MaddyinMilford.