precipitation

Bomb Cyclones | Earth Wise

December 2, 2021 By EarthWise Leave a Comment

It seems like we are hearing about new weather phenomena pretty frequently these days. One name that has popped up lately is “bomb cyclones.” Bomb cyclones, it turns out, are storms that undergo “bombogenesis.” What that means is a low-pressure area (in other words, a storm) that undergoes rapid strengthening and can be described as a weather bomb, or popularly, a bomb cyclone.

These things usually take place over remote tropical ocean areas but a really intense one struck the Pacific Northwest on October 24th. The storm off the coast of Washington, with a barometric pressure reading equivalent to a category 4 hurricane, was the second extreme low-pressure storm in the North Pacific in a single week. Both storms involved pressure drops of more than 24 millibars in 24 hours, making them bomb cyclones.

These storms brought high winds and extreme precipitation that doused wildfires and provided some relief to the extreme drought in Central and Northern California. Along with these positive effects, however, the storms also caused power outages, flooding, landslides, and mud and debris that washed out roads.

The October 24-25 event brought 16.55 inches of rain to Mount Tamalpais in Marin County, California in a 48-hour period. Sacramento got 5.44 inches of rain, breaking a 140-year-old record. And the city had just broken another extreme weather record for the longest dry spell in history.

The storms directed streams of moisture from north of Hawaii toward the West Coast in long, narrow bands of moisture known as atmospheric rivers. We are learning about all sorts of unfamiliar weather phenomena as extreme weather events become increasingly common.

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Extratropical Cyclones Drench West Coast

Photo, posted January 4, 2018, courtesy of NOAA/CIRA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Drought And U.S. Hydropower | Earth Wise

November 29, 2021 By EarthWise Leave a Comment

The ongoing severe drought in the western U.S. has led to low water levels in the rivers and reservoirs that feed hydroelectric power systems. The Energy Information Administration is projecting a 13.9% decrease in hydroelectric generation this year compared to 2020.

Water levels in Lake Powell have fallen so low that it may not be possible to operate the power plant at Glen Canyon Dam starting as soon as 2022. California officials took the Edward Hyatt hydroelectric plant offline in August because of low water levels on Lake Oroville. Washington, the state with the most hydroelectric power generation, has seen an 11% drop in electricity generated to date this year as compared to last year. That state is actually doing better than others in the West, such as California, where hydro generation is down 38%.

Hydropower accounts for over 7% of the electricity generated in the United States. Five states – Washington, Idaho, Vermont, Oregon, and South Dakota – generate at least half of their electricity from hydroelectric dams.

The current decrease in hydropower is alarming, but it is not unprecedented. The more significant question is whether the drop in generation this year is a sign that this power source is declining and becoming less reliable. According to some scientists, the West is in a “megadrought” that could last for decades.

The greater concern is whether the bad years are likely to become more common because of climate change. Climate projections agree that temperatures will continue to rise, but what will happen to precipitation levels in specific places is much less certain. That is what will determine what the future holds for hydroelectric power.

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Inside Clean Energy: Drought is Causing U.S. Hydropower to Have a Rough Year. Is This a Sign of a Long-Term Shift?

Photo, posted May 7, 2014, courtesy of Tyler Bell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Low For Lake Powell | Earth Wise

November 2, 2021 By EarthWise Leave a Comment

Lake Powell is the second largest reservoir by capacity in the United States. It straddles the border of southeastern Utah and northeastern Arizona and was created by the Glen Canyon Dam, completed in 1963. The reservoir serves as a bank account of water that is drawn upon in times of drought and has made it possible to weather extended droughts by sustaining the needs of cities, industries, and agriculture in western states. Hydroelectric power by the dam’s eight generators provides electricity to seven states.

As a result of the protracted drought in the west, the water levels in Lake Powell have reached the lowest point since 1969. As of September 20, the lake held only 30% of its capacity and federal managers started releasing water from upstream reservoirs to help keep Lake Powell from dropping below the so-called minimum power threshold which is the water elevation that must be maintained to keep the dam’s hydropower turbines working properly.

With the entire Lower Colorado River water system below 40% of capacity, Bureau of Reclamation recently announced that water allocations in the U.S. Southwest would be cut over the next year. The Colorado River basin is managed to provide water to millions of people including those in San Diego, Las Vegas, Phoenix, and Los Angeles.

Successive dry winter seasons over the past two years along with a failed 2020 summer southwestern monsoon, have led to the lowest precipitation levels on record in the Southwest going at least as far back as 1895. With warm temperatures, reduced snowpack, and increased evaporation of soil moisture, most of the American West suffers from persistent and widespread drought.

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Lake Powell Reaches New Low

Photo, posted June 28, 2021, courtesy of the USFWS – Mountain Prairie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Understanding Geoengineering | Earth Wise

September 7, 2021 By EarthWise Leave a Comment

The most recent report from the UN Intergovernmental Panel on Climate change includes discussion of a number of extreme and untested solutions to the climate crisis. Among these are solar geoengineering – modifying clouds or spraying tiny reflective particles into the upper atmosphere in order to block some of the sun’s light and thereby cool the planet. The underlying principles are relatively straightforward.

There have been various models that predict the extent to which solar geoengineering would lower the earth’s average temperature. What hasn’t been modeled to any real extent is what other effects it would have.

The new report discusses the results of models that predict how temperatures would vary at different latitudes and how geoengineering would affect rainfall and snowfall. According to the models, releasing sulfate aerosols into the upper atmosphere to block sunlight would lower average precipitation. But every region would be affected differently. Some regions would gain in an artificially cooler world, but others might, for example, suffer by no longer having suitable conditions to grow crops.

The drop in temperature would allow the planet’s carbon sinks (plants, soils, and oceans) to take up more carbon dioxide from the atmosphere. However, as long as people continue to pollute, carbon dioxide would continue to make the oceans more acidic, causing significant harm to marine ecosystems. Furthermore, solar geoengineering would have to be an ongoing process that would go on indefinitely and if it were to suddenly stop, it would lead to rapid warming.

The more we learn about geoengineering, the more it becomes clear that there would be many side effects as well as serious moral, political, and practical issues. Society has to consider if all these things represent too much danger to allow us to seriously consider such a strategy.

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In the New UN Climate Report, a Better Understanding of Solar Geoengineering

Photo, posted September 9, 2012, courtesy of Kelly Nighan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Seeds And Climate Change | Earth Wise

August 19, 2021 By EarthWise Leave a Comment

Farmers and agricultural communities around the world are on the frontlines of climate change. They are among the first to feel the impacts of hotter temperatures as well as more frequent and intense droughts and precipitation. These challenges pose a massive threat to both farmer livelihoods and global food security.

As the planet continues to heat up, many arid regions that already have marginal conditions for agriculture will be increasingly under stress. As a result, researchers from the Massachusetts Institute of Technology and the King Mohammed VI Polytechnic University in Morocco are working on a promising new way to protect seeds from this stress during their crucial germination phase. Their simple and inexpensive process, which was recently described in a paper published in the journal Nature Food, also provides plants with extra nutrition at the same.

The research team has developed a two layer coating for seeds designed for tackling issues related to drought. Drawing inspiration from natural coatings that occur on some seeds like chia seeds, the first layer is designed to protect the seeds from drying out. It provides a gel-like coating that grips any moisture that comes along and surrounds the seed with it. The second (inner) layer of the coating contains preserved microorganisms called rhizobacteria, as well as some nutrients to help the seeds grow.

The materials for the coatings are biodegradable, readily-available, and often used in the food industry already. According to researchers, early tests using common beans have demonstrated encouraging results in Morocco, and more field tests of the seeds are currently underway.

As the climate continues to change, more innovations like this will be necessary for global food security.

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Engineering seeds to resist drought

Photo, posted September 17, 2010, courtesy of Stacy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Caspian Sea And Climate Change | Earth Wise

January 22, 2021 By EarthWise Leave a Comment

According to the National Oceanic and Atmospheric Administration, global sea levels have been rising over the past century, and the rate has increased in recent decades. Sea levels are currently rising about one-eighth of an inch every year.

Sea level rise is caused primarily by two factors related to climate change: the added water from melting glaciers and ice sheets, and the expansion of seawater as it warms. While climate change is causing global sea levels to rise, higher temperatures in other regions are having exactly the opposite effect. The water levels are falling.

According to researchers from the University of Bremen in Germany, the Caspian Sea is a perfect example of how a body of water will change. While it is named a sea due to its size and high salinity, the Caspian Sea is actually a lake. In fact, it’s the largest lake in the world. Its largest inflow is the Volga River and it has no natural connection to the ocean. Its water level is determined by the proportional influences of inflow, precipitation, and evaporation. Climate change is causing increased evaporation, which leads to a declining water level.

According to the research team, the water level of the Caspian Sea could fall by 29 to 59 feet during this century.

The Caspian Sea is surrounded by Kazakhstan, Turkmenistan, Iran, Azerbaijan and Russia. It’s an important regional water reservoir, and a biological and commercial center.

The researchers hope the Caspian Sea will be used as an example in scientific research to assess the vulnerability of other regions to falling water levels.

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Climate crisis is causing lakes to shrink

Photo, posted October 31, 2016, courtesy of Amanderson2 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Widespread Drought | Earth Wise

September 7, 2020 By EarthWise Leave a Comment

As the U.S. enters the last part of the summer, fully one-third of the country is experiencing at least a moderate level of drought. Much of the West is reaching severe drought conditions and New England has been unusually dry and hot. In total, over 50 million Americans are living in drought-affected areas.

According to the U.S. Drought Monitor program, more than 93% of Utah, Colorado, Nevada, and New Mexico are experiencing drought to some degree. More than 60% of both Utah and Colorado are in severe drought. More than three-quarters of Oregon, Arizona, and Wyoming are also in drought. And most of these areas had no sign of drought this time last year.

Severe drought conditions result in stunted and browning crops, limited pasture yields, dust storms, reduced well water levels, and an increase in the number and severity of wildfires.

Warm air temperatures and minimal snowfall in spring set the stage for this summer’s drought conditions. A ridge of high pressure over the northeastern Pacific Ocean pushed the jet stream farther north than usual. And, once again, there has been a failure of the southwestern monsoon in Arizona and New Mexico and the Four Corners region. Monsoon rains provide half of the year’s precipitation in many of those areas.

Instead, there has been extreme heat in the region. Phoenix has already smashed the record for the most days over 110^oF in a calendar year (42 as of August 18), with five months to go. Las Vegas hasn’t seen measurable rainfall since April, and Cedar City, Utah has recorded a record low of 0.05 inches of rain this summer.

Conditions are not expected to get better for a couple of months.

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A Third of the U.S. Faces Drought

Photo, posted May 7, 2014, courtesy of Tyler Bell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Geoengineering And Volcanoes

November 14, 2019 By EarthWise Leave a Comment

Solar geoengineering is a theoretical strategy for curbing the effects of climate change by introducing aerosol particles in the upper atmosphere to reflect some of the Sun’s radiation back into space and thereby cool the planet. It would basically be intentionally tinkering with the climate system on a global scale.

The concept is fraught with the danger of unintended consequences and most experts consider the idea almost unthinkable. But there are those who see it as a last resort if all our other efforts to mitigate the effects of climate change are unsuccessful.

Proponents of the idea like to describe the technique as being like a human-made volcano. Major volcanic eruptions spew ash particles into the atmosphere which can linger for as long as a few years. The result is cooler temperatures, sometimes across much of the globe. The Krakatoa eruption of 1883 lowered average Northern Hemisphere temperatures by more than 2 degrees and created chaotic weather patterns until about 1888.

Researchers at the Carnegie Institution and two Chinese research institutions used sophisticated modeling techniques to compare the effects on the climate of a volcanic eruption with long-term geoengineering deployment.

They found that the volcanic eruption created a greater temperature difference between the land and sea than the geoengineering and resulted in very different precipitation scenarios. In both cases, there would be less available water for people on land.

Overall, the study demonstrated that volcanic eruptions are imperfect analogs for geoengineering and that scientists should be very cautious about extrapolating too much from them. It is important to evaluate geoengineering from an informed position, but the truth is that it represents a great and perilous unknown.

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Geoengineering Versus A Volcano

Photo, posted November 1, 2002, courtesy of the NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

An Upside Of Climate Change

October 15, 2019 By EarthWise Leave a Comment

In contrast with most countries in the world, the main political factions in the United States have very different views of climate change. Somehow, one side of the aisle remains skeptical about the changing climate even as temperature records are broken, arctic ice disappears, and powerful storms become increasingly common.

But putting aside the increasingly inexplicable political schism about climate change, there are instances where the consequences of the warming climate are not all dire. In fact, there are places where climate change is having a positive effect.

One such place is West Virginia, where research studies are finding a real upside to the changing climate.

A recent study of the climate in West Virginia over the period from 1900 to 2016 found the maximum temperatures trended downward, average minimum temperatures ascended, and annual precipitation increased. On average, West Virginians are now seeing cooler summers, warmer winters and wetter weather.

Given these changes, there have been big changes in agriculture. Yields of important crops like hay, corn, winter wheat, and soybeans have all increased. The winter season has shrunk by as much as 20 days and the growing season itself has increased by approximately 13 days. A number of crops that historically did not fare well in West Virginia may now become viable. It may even be possible to pursue double cropping, meaning that the longer growing season may allow farmers to raise one crop, harvest it, and then raise and harvest a second crop within the same year.

In the big picture, climate change is shaping up as a global calamity, but for a few people in certain places – such as West Virginia – it may have some real upside.

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The positive implications of…climate change? WVU researcher sees agricultural, food availability and economic possibilities

Photo, posted November 12, 2014, courtesy of Mike via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The ‘Biggest Ever’ Arctic Expedition

October 3, 2019 By EarthWise Leave a Comment

The Arctic is warming faster than any other region on Earth. In fact, it’s warming at a rate of almost twice the global average. And, since what happens in the Arctic doesn’t stay in the Arctic, the world is already feeling the effects: rising sea levels, changes in climate and precipitation patterns, increasing severe weather events, and so on.

As a result, researchers from more than a dozen countries have launched the biggest and most complex expedition ever attempted in the Arctic. They plan to freeze Germany’s largest research vessel, the Polarstern, into Arctic sea ice, where it will remain trapped for twelve months. The ship will drift with the sea ice as the sea ice drifts. The vessel will serve as a research laboratory, hosting a rotating crew of 300 scientists. The ice, the ocean, the atmosphere, and even the wildlife will all be sampled. This year-long journey will give researchers their closest look at how the polar climate and its fragile ecosystems are changing.

Led by the Alfred Wegener Institute for Polar and Marine Research in Germany, the Multidisciplinary drifting Observatory for the Study of Arctic Climate project (or MOSAiC) is expected to cost about $150 million.

One major goal of MOSAiC is to improve strikingly uncertain climate projections for the Arctic. Climate models disagree on how much more the Arctic will warm as the concentration of greenhouse gases in the atmosphere rises and sea ice shrinks. Some project a 5ºC rise by 2100 relative to the 1986-2005 average. Others predict a 10ºC increase.

Understanding the complex processes occurring in the Arctic is essential for projecting the future impacts of climate change.

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Climate scientists prepare for largest ever Arctic expedition

Climate change: Polarstern leaves for ‘biggest ever’ Arctic expedition

Image courtesy of the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility.

Earth Wise is a production of WAMC Northeast Public Radio.

Intense Rainfall And Crops

July 2, 2019 By EarthWise Leave a Comment

The warming of the planet does not necessarily imply local weather will be warmer or drier than average. While heatwaves and droughts are increasingly common events in many places, so are intense rain events.

A new study led by scientists at the University of Illinois has found that intense rainfall is as damaging to the U.S. agricultural sector as heatwaves and excessive droughts.

The study examined more than three decades of crop insurance, climate, soil, and corn yield data. Researchers found that since 1981, corn yields in the U.S. Midwest were reduced by as much as 34% during years with excessive rainfall. Years with drought and heatwaves experienced yield losses of up to 37%.

Intense rain events can physically damage crops, delay planting and harvesting, restrict root growth, and cause oxygen deficiency and nutrient loss. The study estimated that between 1989 and 2016, excessive rainfall caused $10 billion in agricultural losses. However, excessive rainfall can have either negative or positive impact on crop yield and the effects can vary regionally.

Parts of the Midwest have already experienced a 42% increase in the heaviest precipitation events since 1958. Climate change models predict that much of this region will experience even more frequent and intense precipitation events in the coming decade.

According to the study, excessive rainfall is the major cause of crop damage currently in the U.S. for corn, and also has broad impacts for other staple crops such as soybeans and wheat. The authors suggest that as rainfall becomes more extreme, reforms will be needed in the U.S. crop insurance industry in order to better meet planting challenges faced by farmers.

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Intense Rainfall Is As Damaging to Crops As Heatwaves and Drought, and Climate Change Is Making It Worse

Photo, posted October 2, 2013, courtesy of the United Soybean Board via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Rainy May

June 27, 2019 By EarthWise Leave a Comment

If it seemed like May was unusually rainy, that’s because it was. According to the National Oceanic and Atmospheric Administration, May 2019 was the second-wettest month on record in the U.S. and contributed to a record-setting wet 12-month period.

The average precipitation for May was 4.41 inches, which is 1.5 inches above normal. The wettest month in 125 years of record keeping was May 2015, which averaged just 0.03 inches more than this past May.

The period from June 2018 through May 2019 saw the wettest 12-month period on record in the U.S. with 37.68 inches, nearly 8 inches above average. Increases in heavy rain events are among the most anticipated and well-documented impacts from climate change.

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During May, the stormy pattern led to widespread flooding in the nation’s heartland. In North Carolina, early-season extreme heat and a rapidly-developing drought was replaced by intense rainfall and flooding.

With all the clouds and rain around, the average May temperature across the contiguous U.S. was 59.5 degrees, which ranked in the bottom third of the 125-year record.

Extreme and unusual weather is becoming commonplace as the climate changes. Duluth, Minnesota had 10.6 inches of snow on May 9, breaking an all-time record for May. Denver had its snowiest May in 77 years. But while the U.S. experienced somewhat cooler weather than usual, the planet as a whole continues to warm. April 2019 was the second hottest April on record, dating back to 1880. The Arctic region saw a record low for sea ice.

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Rain-soaked U.S. had its 2nd-wettest month on record in May

Photo, posted May 20, 2013, courtesy of Flickr.

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Earth Wise is a production of WAMC Northeast Public Radio.

Weather-Responsive Traffic Signals

April 17, 2019 By EarthWise Leave a Comment

We all spend time sitting at red lights – sometimes it seems like a whole lot of time. There is a fair amount of science applied in the design of traffic signals that at least has the aim of easing congestion and improving traffic safety.

Signals in modern cities are timed using optimization models that analyze multiple factors including traffic volume and speed with the goal of safely getting as many vehicles as possible through intersections. It sure doesn’t seem that way in many places, but that is the intent in any case.

But a real problem with these models is that they assume normal conditions including weather conditions. In places that experience real winter conditions, the assumptions of traffic models fail. If the road surface is covered with snow and ice and visibility is poor, variables like speed and stopping distances become very different.

Researchers at the University of Waterloo in Canada collected data from real-world intersections and ran computer simulations to determine the effects of adjusting traffic signal behavior in bad weather (as well as in the presence of other conditions such as accidents or construction.) They found that such adjustments could reduce traffic delays by as much as 20%.

Cities with computerized signal systems are already equipped to remotely and inexpensively adjust the timing of traffic lights. To gain the benefits of smarter signals, there would need to be video cameras and a certain amount of artificial intelligence software that would be able to automatically tweak the timing of lights in response to traffic changes caused by weather, accidents or construction.

It sounds like a great idea.

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Weather-responsive intersections could ease traffic congestion

Photo, posted September 22, 2009, courtesy of Tristan Bowersox via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

California Fires And Precipitation

April 11, 2019 By EarthWise Leave a Comment

Two things we have heard a lot about in recent years have been the persistent drought in California and the terrible wildfires the state has experienced. Along the way, the state has had some pretty wet and snowy winters. This past winter, the California snow pack has seen incredible levels building up, which is great news for the state’s farmers. But does that also mean that the next year should see some relief from severe wildfires?

The answer appears to be no. A new study from an international team that includes the University of Arizona has comprehensively looked at the amount of winter precipitation in California and the severity of the subsequent wildfire season.

The position of the North Pacific jetstream over California is strongly linked to the amount of winter precipitation. This has been true for hundreds of years and continues to be the case.

From 1600 to 1903, the linkage between winter precipitation and wildfire severity was also very strong. But after 1904, that connection weakened. As a result, fire suppression policies were instituted. When fires arose, they were put out as quickly as possible. The result over time is fuel buildup, making larger fires far more likely.

According to the new study, after 1977, the connection between winter precipitation and wildfire severity disappeared entirely. There no longer appears to be any relationship between jet stream dynamics and fire. The warming climate and the results of fire suppression dominate the potential for wildfire. California’s wet winter of 2016-2017 provides a good example. That winter was followed by many large fires in 2017.

So, this very wet winter in California does not imply that this should be a year without severe wildfires.

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Wildfire Risk in California No Longer Coupled to Winter Precipitation

Photo, posted July 26, 2018, courtesy of Bureau of Land Management California via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

2018 Was A Wet Year

March 20, 2019 By EarthWise Leave a Comment

Recent news reports noted that 2018 was the fourth hottest year on record. But the changing climate is not just about temperature. 2018 was also the third-wettest year since 1895, when steady record-keeping began.

Overall, the U.S. recorded 4.68 inches more precipitation in 2018 than the 20th century average. But all that rain and snow was nothing like evenly distributed. The eastern half of the country – especially in places like North Carolina and Virginia – saw record amounts of precipitation, while most of the West remained stuck in drought.

The warming climate leads to precipitation extremes at both ends, meaning that wet places are likely to get wetter and dry places drier. There has been a marked upward trend in short-duration extreme events. For example, Cyclone Mekunu dumped almost 13 inches of rain on Salalah, Oman in 36 hours, more than double its annual average rainfall.

In the southeast and eastern U.S., the trend toward stronger storm events is mostly driven by strong warming of the oceans that fringe their shores. Warm oceans evaporate more water into the air and warm air holds more water than cooler air. Warmer, moisture-laden air acts like a blanket over the land, keeping heat trapped near the ground. Many of the states that had their wettest-ever years also set records for high minimum temperatures – their coldest temperatures were less cold than in the past.

Air temperatures are projected to warm up even further in the coming years and, as a result, many scientists are anticipating that extreme precipitation events will only get more extreme. The pattern of drought in the west and wetness in the east is likely to stay.

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2018 was the U.S.’s third-wettest year on record—here’s why

Photo, posted August 18, 2018, courtesy of Jim Lukach via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And The Polar Vortex

February 20, 2019 By EarthWise Leave a Comment

This winter has seen some brutally-cold weather in many places, some of it record-breaking. Predictably, some climate-change deniers point to this as evidence that the climate is not warming at all. They are quite wrong.

For starters, it is essential to understand the difference between climate and weather. Climate is the average weather patterns in a region over extended periods of time. Weather is the short-term fluctuations in temperature, precipitation, barometric pressure, wind, and so forth. There can be extremes in weather of many types in a given climate region including very cold weather in a warming climate.

The recent cold weather events in the U.S. stem from the flow of Arctic air into southern regions. Such flows are impacted dramatically by the behavior of the jet stream. These high-altitude east-to-west winds are driven by temperature differences between cold arctic air and warm tropical air and play a huge role in our weather.

The Arctic has seen extremely unusual warming due to the changing climate, weakening and fracturing the polar vortex, which is a persistent low-pressure area near the pole. The changing air flow from the Arctic causes the jet stream to take wild swings. When it swings further south, it causes cold air to reach farther south. These swings tend to hang around for a while, leading to extended periods of cold weather in the winter and, actually, extended periods of warm weather or even droughts in the summer. Studies have predicted that extreme, deadly weather events could increase by as much as fifty percent by 2100.

As more Arctic air flows into southern regions, North America can expect to see harsher winters. The warming climate doesn’t always lead to warmer weather.

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