As thousands of people across the Northeast shovel out their driveways and trudge through the slushy remains of Winter Storm Nemo, climate experts continue to debate what caused the storm.
“Upward linear trends” in snowfall persisted throughout the 20th century, according to a report by the American Meteorological Society. On average, storms like blizzards, rainstorms and hurricanes have become 30 percent more frequent in the United States over the past 60 years and will only continue to increase as the earth warms, according to a report by the Environment America Research and Policy Center.
Warmer ocean temperatures have resulted in increased moisture in the air, which can lead to heavier precipitation from storms originating over the seas. Melting ice in the Arctic has led to changes in air pressure and a shift in the jet stream that has put it into contact with the moist ocean air, creating the necessary conditions for strong storms, according to a report by the Union of Concerned Scientists.
Having two destructive storms in the region only several months apart — Hurricane Sandy last October and Winter Storm Nemo last week — has fueled arguments from climate scientists that severe weather patterns will continue to develop.
“Rising ocean surface temperatures have already increased the temperature and moisture content of the air … setting the stage for heavier snow and rain storms,” wrote Brenda Ekwurzel, a climate scientist with the Climate and Energy program at the Union of Concerned Scientists, in a Huffington Post article.
But some argue the storms do not provide enough evidence to draw conclusions about how climate change may affect weather. These types of storms are not unprecedented in this region, and having two such powerful storms within the span of four months does not illustrate future climate patterns, said Mark Seefeldt, an adjunct assistant professor of physics at Providence College who specializes in polar meteorology. Nemo is the fourth biggest snowstorm on record to hit Providence, but three of the top 10 occurred 50 years ago between 1960 and 1962. A “theoretical connection” between global warming and powerful storms is not enough to attribute every recent natural disaster to climate change, he said.
Changes in regional climate can affect weather for years to come without necessarily being a product of climate change, said Baylor Fox-Kemper, assistant professor of geological sciences. For example, North Atlantic oscillation, which is the change in the circulation of the jet stream and its interaction with ocean temperature, can affect the weather, he said.
Even though a single weather event does not signal the overall climate trends for years, it is possible that the “dice get subtly loaded by climate,” Fox-Kemper said. Increased moisture in the air due to global warming could contribute to events like wildfires, droughts and tornado activity, he said. Local ecosystems are affected by changes in weather and will need to adapt if storms like Nemo and Sandy become more frequent, he added.
There are three different strategies that could be implemented to address climate change and the impact of future storms, Fox-Kemper said. Governments can either spend money to fix weather-related issues as they arise or implement policies to reduce overall greenhouse gas emissions. They could also undertake a more aggressive approach — geo-engineering — in which people could deliberately alter the climate to reverse changes already made. For example, dust could be put into the atmosphere to mimic the cooling effect of volcanic dust. But this approach could have many unforeseen consequences that are not necessarily beneficial, Fox-Kemper said.
Governments will balance interests of the present generations with those of the future in determining policy, Fox-Kemper said.
Regions should exercise caution and conduct a cost-benefit analysis before allocating resources to deal with weather-related issues, Seefeldt said. Cities should not waste money on equipment that is not going to be regularly used in response to a few devastating storms.
Though the impact of storms like Sandy and Nemo can be devastating, “the variations in weather are part of what makes the Earth a place that is habitable for us,” Fox-Kemper said.
An previous version of this article reported that changes to the Arctic climate were establishing conditions conducive to strong storms and attributed this to a report by the Union of Concerned Scientists. In fact, the 2013 report stated that some scientists believe this may be the case.