What Climate Change Means for Summer in the United States - Center for Climate and Life

What Climate Change Means for Summer in the United States - Center for Climate and Life

Photo: Johnny Chau/Unsplash

Labor Day weekend marks a change of seasons: summer drawing to a close, school back in session, wearing white a potential social blunder. It’s also a time for reflection on the season. Summer is a much-anticipated time across the Northern Hemisphere, especially after a long and brutal winter. As global temperatures continue to inch up as a result of rising greenhouse gas emissions, summer will change in numerous ways.

Extreme Heat

As global temperatures rise, summers will continue to grow hotter, posing health risks due to acute heat and humidity, especially in urban areas. If emissions continue at their present rate, by 2100 New York City will have 30 extreme heat days each year—days where the temperature is greater than 100 degrees Fahrenheit—compared to the current average of three to four days per year.

More heat also leads to decreased moisture in soils and vegetation, creating ideal conditions for drought and even wildfires. As certain regions become hotter due to climate change, we can expect wildfires to increase in areas previously not thought to be highly prone to fire danger.

“Summer heat is a major promoter of forest fires in many regions globally,” said Park Williams, a Lamont-Doherty Earth Observatory hydroclimatologist and 2016 Center for Climate and Life Fellow. “This effect is non-linear such that heat becomes increasingly able to promote fire as it warms.”

Rainfall

Rain can quickly ruin summer plans. Climate models project that overall summer precipitation in large parts of the United States will decrease due to climate change. This may be good for outdoor enthusiasts, but a lack of rain can lead to drought. Dry, compacted soils don’t promote the absorption of rainfall so intense rain can lead to flooding,

And even though there will be less rain overall, models suggest there will be a greater number of heavy rainfall events. “This is because of the increased water holding capacity of the atmosphere as temperature rises (the Clausius-Clapeyron relation),” said Mingfang Ting, a Lamont atmospheric scientist. “With everything else being equal, a higher amount of moisture in the atmosphere will lead to heavier precipitation during a summer storm.”

Agriculture

Summer offers the opportunity to purchase fresh, local produce. As summers in the U.S. grow increasingly hotter and drier, crop yields will begin to fall. Certain crops may become vulnerable to disease and pest outbreaks. Decreased rainfall in the Southwestern U.S. will strain reservoirs used for irrigation, leading water to be drawn from soil and nearby streams. Heat stresses will also harm farm laborers and livestock.

As summers in the U.S. grow increasingly hotter and drier, crop yields will begin to fall. (Photo: Michal Bielejewski)

“To adapt, U.S. agriculture will require considerable advance planning in what crops to grow and where, shifts towards crops more tolerant of drought and heat, changes in agricultural practices such as soil management, development of new varieties of crops and livestock that can handle the changing climate, and changes in policies on farm support, crop insurance, disaster relief,” said Richard Seager, a Lamont climate scientist.

This can have great effects both on local produce and even the entire farming industry, while efforts to combat climate change may also have consequential effects on agriculture.

“Efforts to rapidly decarbonize our energy systems have not sufficiently considered the direct or indirect impacts on our food system,” said Michael Puma, a 2016 Center for Climate and Life Fellow who studies food security, “This stands out as a major risk moving forward: That is, inadvertently destabilizing global food production through carbon regulation.”

Puma says it’s important to make sure there is proper planning and research to ensure agriculture can adapt as governments make laws to decrease carbon emissions.

Vegetation

Agricultural crops aren’t the only plants that may be displaced due to climate change. In many places, summer transforms the landscape from barren, brown earth to a green, flourishing paradise. Yet the changing climate is reducing suitability and stressing many native plant species. Invasive plant species, on the other hand, often benefit from warmer temperatures. As it becomes warmer, trees can become more susceptible to drought, pests such as bark beetles, and wildfires.

“Large organisms, such as forest trees, are adapted to stability by having long generational turnover, defining their own ecosystems and weathering climatic extremes,” said Tammo Reichgelt, a Lamont paleoecologist. “That doesn’t work when the climate is changing and we’re creating disturbance faster than the amount of time it takes for a generation to turn over.”

This can cause native tree species to decline and invasive, non-native species to thrive. Reichgelt says climate change has the capacity to transform forests in many parts of the U.S. by filling them with weedy plant life.

Coastlines

Some people find nothing is more idyllic than a summer beach vacation. If you stand at the water’s edge today and turn to look back where your eyes trace the land, about six feet higher than your feet at the water’s edge, you will see where the shoreline could be by 2100. This is because as the global temperature increases, polar ice sheets melt and warmer seawater expands, both causing sea levels to rise around the globe.

Maureen Raymo, a Lamont paleoclimatologist, says sea level rise is slow, but accelerating. She warns that if polar ice continues to melt, most major coastal cities will eventually be flooded.

A reduction in beach sizes, the destruction of homes and businesses near water, changes in beach ecology, flooding and stress on beach, dock, and coastal road access, are among other predicted sea level rise impacts. And as beaches grow smaller and more expensive to maintain, coastal real estate prices will lose value as flood zones expand.

What can we do?

It’s important to know that Earth is not past a point of no return, despite these myriad changes. More research, such as that being initiated by the Center for Climate, is needed to fully understand the impacts of climate change and find solutions. On a global level, the Paris Agreement and other initiatives aim to cut carbon emissions, while communities, cities, states, and businesses are adopting more sustainable practices. Together, these initiatives and individual action aimed at reducing fossil fuel emissions can help ensure we’re able to enjoy future summers.  

Explore the Center for Climate and Life website to learn more about how it’s leading the search for solutions.

— Nicole deRoberts