Stormy Skies in a Changing Climate

Increased Flooding

According to the U.S. National Climate Assessment, the amount of rain falling in powerful downpour events has been significantly above average since 1991. Further, sea-level rise has worsened the impacts of storm surge, causing ocean water to flood communities even further inland along the coast when weather events like hurricanes occur.  In 2015, severe storms cost over $10 billion in property damages in the U.S.

The cause of heavy downpours is well understood — as the climate continues to warm, the air’s capacity for water vapor increases — for each degree increase the capacity is expected to increase by 7 percent. Global studies have shown that the amount of water vapor in the atmosphere has already increased due to human-caused warming. The added moisture in the air is then picked up by storms, which results in extreme weather.

Flooding, which also results from other climate impacts such as more rapid snowmelt and greater storm surge from sea-level rise, will be exacerbated by extreme precipitation events. Flooding has far reaching impacts — in addition to property and agricultural damage (which has averaged nearly $8 billion annually from 1981 through 2011), flooding can increase the risk of landslides and spread pollution to water sources like lakes and rivers. This damages aquatic ecosystems and the wildlife like fish, birds, and others that depend on them.

In addition to heavy rain and flooding, extreme weather like hurricanes can also be impacted by climate change. According to the National Climate Assessment, the intensity, frequency, and duration of hurricanes in the North Atlantic has increased since the 1980’s.

Further, the frequency of the strongest hurricanes has also risen, i.e., category 4 and 5 storms such as Hurricane Matthew, which recently pummeled Haiti before traveling over the Southeastern U.S. as a category 2 storm- resulting in 17 deaths in the US and over 1000 in Haiti. As the climate continues to change, hurricane intensity and heavy rainfall are also expected to increase further, posing a growing threat to wildlife, habitat, and communities.

Flooding in Baton Rouge

The flooding that hit Louisiana this summer is the worst natural disaster to hit the U.S. since Superstorm Sandy. Thousands of people were displaced, and many of them are still waiting for their homes to become livable again. According to Louisiana’s Governor, the floods caused at least $8.7 billion in damages and FEMA reported more than 134,000 households had registered for aid. The flooding shut down over 7,000 local businesses, according to the Joint Katrina Task Force commander.

States like Louisiana are on the front lines of the climate impacts. Events that are expected to occur every 100 or 500 years are becoming an annual phenomenon. In communities that remember when floodwaters began to rise from Hurricane Katrina, many are wondering when the next disaster will strike.

What Comes Next?

If climate change continues at its current pace, the impacts of hurricanes, heavy precipitation, and flooding will increase. Two actions must be taken: the source of human-caused climate change must be addressed through economy-wide reductions in carbon pollution, and the impacts of extreme weather must be prepared for in a proactive manner.

One of the most effective policy mechanisms for reducing carbon pollution across the economy is a carbon price. Scientists and economists alike agree that attaching a cost to pollution is an effective path toward rapidly reducing it, either through a cap-and-trade program or through a carbon tax (or some hybrid of the two). It is critical that Congress act swiftly to implement federal climate policy. Lack of action is no longer safe for people, our economy, or our treasured natural resources.

Adapting to a changing climate is the other half of the solution – decision makers at all levels should support building and expanding natural systems, known as “green infrastructure,” to protect communities, habitat, and wildlife from the more severe impacts of climate change. Heavy downpours can overwhelm urban drainage systems and cause rivers to rise past their banks and hurricanes can cause extensive damage to coastal communities.

Some examples of actions that can be taken include restoring green infrastructure such as wetlands, which absorb and hold water, and excluding floodplains from risky development projects. Such measures can safeguard communities and wildlife by bolstering the ability of the landscape to buffer against flooding and storm damage.

Through reducing carbon pollution and taking a proactive approach to green infrastructure planning and climate adaptation, it is possible to meet the growing threat of a warming world.