How global warming is changing Richmond’s summers

RICHMOND, Va. (WWBT) - You aren’t imagining it, Richmond’s summer heat and humidity are getting worse, and global warming plays a part.

Dr. Jeremy Hoffman from the Science Museum of Virginia uses colorful language to describe it, saying, “The middle of summer [in Richmond] feels like you’re walking around outside in someone else’s mouth.”

Since 1970, we’ve seen average daytime highs go up by about 3 degrees Fahrenheit. Twenty years ago, our hottest week of the year had average highs in the upper 80s; now, it’s 90°. This data from the National Weather Service gets updated every 10 years. The data in the chart shows the 1990-2020 averages.

An even bigger impact has come at night when low temperatures have climbed 4° since 1970. Some of that overnight climb is due to the urban heat island effect, which is when buildings, pavement, and air conditioning are literally warming us overnight.

Another piece of that nighttime warming is due to increased humidity. Warmer air holds more moisture, and as you add more humidity to the air, it doesn’t cool as far overnight.

As temperatures warm up, the air conditioning season lasts longer, which makes our power bill go up.

Air conditioning is a great innovation, leading to high comfort indoors during heat waves. Still, some people don’t have air conditioning or can’t afford to run it as often, which can cause heat-related illnesses.

Dr. Hoffman led a study in 2017 that showed poorer neighborhoods with minority populations got hotter than Richmond’s wealthiest areas. That’s because there are fewer trees and more pavement. Skinnier streets and mature trees can help make our hottest days more bearable.

Read more on his research here: “Throwing Shade.”

One of the forecasted and verified results of climate change is heavier downpours. If you think of the atmosphere like a sponge, it makes sense. The warmer the air is, the more water it can soak up and hold. But when a storm comes and “wrings out” the sponge, there’s more rain. Global warming is making our heavy rain days heavier.

This is leading to more frequent flash flooding and urban flooding, and the expectation is that this trend will continue as the world continues to warm.

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