Quantcast
Environmental News for a Healthier Planet and Life

Help Support EcoWatch

Study Shows How Arctic Warming is Altering Weather Patterns

Climate

Climate Central

By Andrew Freedman

By showing that Arctic climate change is no longer just a problem for the polar bear, a new study may finally dispel the view that what happens in the Arctic, stays in the Arctic.

The study, by Jennifer Francis of Rutgers University and Stephen Vavrus of the University of Wisconsin-Madison, ties rapid Arctic climate change to high-impact, extreme weather events in the U.S. and Europe.

The study shows that by changing the temperature balance between the Arctic and mid-latitudes, rapid Arctic warming is altering the course of the jet stream, which steers weather systems from west to east around the hemisphere. The Arctic has been warming about twice as fast as the rest of the Northern Hemisphere, due to a combination of human emissions of greenhouse gases and unique feedbacks built into the Arctic climate system.

The jet stream, the study says, is becoming “wavier,” with steeper troughs and higher ridges. Weather systems are progressing more slowly, raising the chances for long-duration extreme events, like droughts, floods and heat waves.

“[The] tendency for weather to hang around longer is going to favor extreme weather conditions that are related to persistent weather patterns,” said Francis, the study’s lead author.

One does not have to look hard to find an example of an extreme event that resulted from a huge, slow-moving swing in the jet stream. It was a stuck or “blocking weather pattern”—with a massive dome of high pressure parked across the eastern U.S. for more than a week—that led to the remarkable March heat wave that sent temperatures in the Midwest and Northeast soaring into the 80s. In some locations, temperatures spiked to more than 40 degrees above average for that time of year.

The strong area of high pressure shunted the jet stream far north into Canada. At one point during the heat wave, a jetliner flying at 30,000 feet could’ve hitched a ride on the jet stream from Texas straight north to Hudson Bay, Canada. In the U.S., more than 14,000 warm-weather records (record-warm daytime highs and record-warm overnight lows) were set or tied during the month of March, compared to about 700 cold records. 

According to the study, Arctic climate change may increase the odds that such high-impact, blocking weather patterns will occur. The study cites examples of other patterns that led to extreme events that also may bear Arctic fingerprints, including the 2011 Texas drought and heat wave, which cost the state’s agricultural sector a staggering $7.62 billion—making it the most expensive one-year drought in that state’s history.

 

Surface temperature departures from average during the March heat wave. Credit: NOAA/ESRL

In addition, the study also mentions jet stream configurations that led to heavy snows in the Northeast and Europe during recent winters. Such events are also “consistent” with the study’s findings, according to the paper.

The reasons why the Arctic is heating up so quickly, a phenomenon known as “Arctic amplification,” has to do with factors that are unique to the Arctic environment, involving feedbacks between sea ice, snow, water vapor and clouds. As the area warms in response to manmade greenhouse gases, melting ice and snow allow exposed land and water to absorb more of the Sun’s heat, which melts more ice and snow, and so on. A relatively small amount of initial warming can be greatly magnified in the Far North. 

The temperature contrast between the frigid Arctic and the milder mid-latitudes is what drives the powerful jet stream winds, which are so important for determining day-to-day weather conditions.

In addition to making the jet stream have more pronounced north/south swings, the reduced temperature gradient between northern and southern areas is causing the westerly component of upper-level winds to slow, especially during the fall when extra heating in the Arctic is exceptionally strong.

The westerly component of upper-level winds during the fall has weakened by about 14 percent since 1979, the study found. 

A slight slowdown in the jet stream may not sound like a big deal. After all, jet stream winds have been clocked at upwards of 200 mph. But it turns out that slowing of the jet stream influences its shape and the motion of individual storm systems. 

Path of the jet stream on March 21, 2012. Credit: weatherunderground

Weaker westerly winds causes the big north/south swings in the jet stream to move more slowly from west to east, making weather conditions in a given location more persistent than they used to be. “That means that whatever weather you’re experiencing now is going to tend to hang around longer because the passage of those waves is really what causes the weather to change,” Francis said.

The study contains a stark warning about future weather patterns, given projections showing that Arctic climate change is likely to accelerate in coming years. “As the Arctic sea ice cover continues to disappear and the snow cover melts ever earlier over vast regions of Eurasia and North America, it is expected that large-scale circulation patterns throughout the northern hemisphere will become increasingly influenced by Arctic amplification,” the study reports.

In other words, rapid Arctic warming is expected to exert a growing influence on the weather far beyond the Arctic Circle, for many years to come.

For more information, click here.

EcoWatch Daily Newsletter

Residents plant mangroves on the coast of West Aceh District in Indonesia on Feb. 21, 2020. Mangroves play a crucial role in stabilizing the coastline, providing protection from storms, waves and tidal erosion. Dekyon Eon / Opn Images / Barcroft Media via Getty Images

Mangroves play a vital role in capturing carbon from the atmosphere. Mangrove forests are tremendous assets in the fight to stem the climate crisis. They store more carbon than a rainforest of the same size.

Read More Show Less
UN World Oceans Day is usually an invite-only affair at the UN headquarters in New York, but this year anyone can join in by following the live stream on the UNWOD website from 10 a.m. to 5 p.m. EST. https://unworldoceansday.org/

Monday is World Oceans Day, but how can you celebrate our blue planet while social distancing?

Read More Show Less
Cryptococcus yeasts (pictured), including ones that are hybrids, can cause life-threatening infections in primarily immunocompromised people. KATERYNA KON/SCIENCE PHOTO LIBRARY / Getty Images

By Jacob L. Steenwyk and Antonis Rokas

From the mythical minotaur to the mule, creatures created from merging two or more distinct organisms – hybrids – have played defining roles in human history and culture. However, not all hybrids are as fantastic as the minotaur or as dependable as the mule; in fact, some of them cause human diseases.

Read More Show Less
National Trails Day 2020 is now titled In Solidarity, AHS Suspends Promotion of National Trails Day 2020. The American Hiking Society is seeking to amplify Black voices in the outdoor community and advocate for equal access to the outdoors. Klaus Vedfelt / DigitalVision / Getty Images

This Saturday, June 6, marks National Trails Day, an annual celebration of the remarkable recreational, scenic and hiking trails that crisscross parks nationwide. The event, which started in 1993, honors the National Trail System and calls for volunteers to help with trail maintenance in parks across the country.

Read More Show Less
Indigenous people from the Parque das Tribos community mourn the death of Chief Messias of the Kokama tribe from Covid-19, in Manaus, Brazil, on May 14, 2020. MICHAEL DANTAS / AFP / Getty Images

By John Letzing

This past Wednesday, when some previously hard-hit countries were able to register daily COVID-19 infections in the single digits, the Navajo Nation – a 71,000 square-kilometer (27,000-square-mile) expanse of the western US – reported 54 new cases of what's referred to locally as "Dikos Ntsaaígíí-19."

Read More Show Less
World Environment Day was put into motion almost fifty years ago by the United Nations as a response to a multitude of environmental threats. RicardoImagen / Getty Images

It's a different kind of World Environment Day this year. In prior years, it might have been enough to plant a tree, spend some extra time in the garden, or teach kids the importance of recycling. This year we have heavier tasks at hand. It's been months since we've been able to spend sufficient time outside, and as we lustfully watch the beauty of a new spring through our kitchen's glass windows, we have to decide how we'll interact with the natural world on our release, and how we can prevent, or be equipped to handle, future threats against our wellbeing.

Read More Show Less

Trending

Experts are worried that COVID-19, a primarily respiratory and airway disease, could have permanent effects on lungs, inhibiting the ability for divers to continue diving. Tiffany Duong / Ocean Rebels

Scuba divers around the world are holding their metaphorical breath to see if a coronavirus infection affects the ability to dive.

Read More Show Less