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In the Northern Hemisphere, deciduous trees are beginning to come out of their dormant season and unfurl their leaves. Soon, the greys and browns that characterize America’s broadleaf forests during winter will be replaced the by the greens of spring and summer. Over the last four decades, there has been a global trend in the [...]

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Over the past 250 years, the amount of carbon dioxide (CO2) in the atmosphere has risen from 280 parts per million to almost 400. Plants use sunlight to convert this atmospheric carbon into the sugars and starches that make up their tissues. As the amount of carbon in the atmosphere changes, plant growth patterns change [...]

The temperature/pressure difference between the equatorial regions and the poles is at its maximum during the winter months. The energy this difference generates is thought to power the “storm tracks,” or the bands in the mid-latitudes where east to west traveling storms (cyclonic high and low pressure systems) are most common. The storm track over [...]

Snowfall and snow cover have direct effects on transportation, soil freeze/thaw cycles, water availability, flood frequency, water quality, wildlife, forest fires and more.
Far from being just a passive product of prevailing climatic conditions, snow cover also influences climate by changing the surface albedo, the amount of solar radiation a surface reflects. The presence of snow, [...]

While commonly considered two separate lakes, Lakes Michigan and Huron are actually hydrologically one body of water – they are connected at the Straits of Mackinaw and rise and fall in unison. Since 1980, Lake Michigan-Huron has been warming and annually averaged surface temperatures are now 3.6 degrees Fahrenheit warmer than they were in the [...]

In the Canadian Arctic, Musk Oxen endure the long winters and short summers that characterize one of Earth’s most extreme environments. The animals have spent millennia adapting to the brutal cold, but now increases in temperature are presenting new problems. A parasitic species of nematode dwells in the musk oxen lungs and too many nematodes [...]

Much attention has been given to the decline of sea ice over the North Pole, which fell to a September minimum of 1.6 million square miles in 2007, about 40 percent below normal levels. On the other side of the world, the sea ice that extends from Antarctica’s continental ice sheets out over the ocean [...]

Near the center of Antarctica in the polar vortex, strong westerly winds that blow in a circle around the continent during winter trap an envelope of air near the South Pole, prohibiting this air from mixing with warmer air masses closer to the equator. The extreme cold in the vortex causes clouds to form in [...]

About 17 percent of America’s total land area is devoted to agriculture and agricultural activities.  Half of America’s domestically consumed produce is grown in California, where fruits and nuts are economically important crops. Fruits and nuts require periods each year of cold temperatures (below 45 degrees Fahrenheit) in order to properly develop. Since the 1950’s, [...]

During winter, Lake Superior’s cold water is on the surface and warm water is on the bottom; during summer, the opposite is the case. The “switchover” happens in the late spring or early summer and is an important event, as it “stirs” the water. This stirring brings nutrients (which feed the lake’s wildlife) from the [...]

Over the second-half of the 20th century, the Southeast experienced an overall decline in annual rainfall levels along with a 20 percent increase in the frequency of extreme (top first percentile) rainfall events. Looking at the 20th century as a whole, there have been significant changes in the seasonal distribution of precipitation, with strong increases [...]

Many of America’s most important commercial crops require between 400 and 1800 hours each winter when the temperature is below 45 degrees Fahrenheit. Winter temperatures have been rising steadily across the nation, with the most pronounced trends being witnessed in the upper-Midwest and Northeast. In fact, winter temperatures are rising faster than temperatures in any [...]

About 75 percent of the West’s water resources originate in snowpack. Most precipitation in the region occurs during the winter, the period of the year when the reservoirs are replenished after the dry summer and early fall months. The reservoirs are at their high points in the spring. Traditionally, snowpack would last into the late [...]

Since 1982, spring in East Asia (defined here as the eastern third of China and the Korean Peninsula) has been warming at a rate of one degree Fahrenheit per decade. In late winter or spring, plants come out of dormancy and produce leaves when the cumulative temperature exceeds a certain threshold. Because temperatures are now [...]

Dust in the atmosphere works to reflect incoming (shortwave) radiation, working to cool the Earth, and it also absorbs outgoing (longwave) radiation, which works to warm the planet. Each of the world’s major crustal dust sources (such as the Gobi, the Sahara Desert, and the Lake Chad Basin) have distinct “signatures” composed of relative concentrations [...]

The Indian Monsoon is a system of winds that travel from the relatively cool ocean to the relatively warm continent during the summer months (the wet season) and from the cool continent to the warm ocean during the winter months (the dry season). A greater temperature contrast between the ocean and the land makes a [...]