Subscribe Now

Discussions of climate and climate variability often focus on temperature trends at the Earth’s surface, which is where humans spend most of their time. But the atmosphere holds onto little energy compared to the oceans – the top few feet of the ocean holds as much heat as the entire atmosphere above it! Transfers and [...]

In Brief: The recent weakness in the East African long rains has been linked to persistently elevated temperatures in the western tropical Pacific. Rains in East Africa primarily fall during the long rains (March through May) and the short rains (October through December). Understanding how climate and climate change influence these rains is particularly important [...]

In Brief: Variability in North Pacific atmospheric circulation systems affects the timing and strength of the upwelling that occurs along the California Coast, impacting the productivity of the waters there. Earth’s ocean is mixed by a complex system of currents. Downwellings occur when currents move water from the surface to the depths and upwellings occur [...]

Two large scale circulation patterns, the Arctic Oscillation and the El Niño-Southern Oscillation, have proven useful for predicting winter weather in different areas of the United States. AO: The Arctic Oscillation (AO) is the difference in atmospheric pressure between the Arctic and the mid-latitudes of the Northern Hemisphere. Upper-atmospheric westerly winds and mid-latitude winter storms [...]

In Brief: Periods of increased stratospheric aerosol content over the past 50 years likely dampened the  warming trend. Volcanic eruptions can cool the Earth by injecting sulfur up into the stratosphere, the second layer of the atmosphere between five and 30 miles in altitude. The volcanoes increase stratospheric levels of tiny droplets of sulfuric acid, [...]

In Brief: Plants, particularly in the Amazon, influence their climate by moving moisture from the soil into the atmosphere – less when the soil is dry and more when the soil is wet. This helps to maintain both wet and dry rainfall regimes. Every place in the world has its own climate with its own [...]

In Brief: The extent of older Arctic sea ice, or ice that has survived at least one melt season, has been declining since 1980 with a melt rate acceleration beginning around 2002. The 2007 September Arctic sea ice minimum extent was the smallest on record. This ice has been in a declining trend since 2002, [...]

In Brief: The 1783-84 eruption of Iceland’s Laki volcano caused crop failures and a cold summer in North America, while the following winter’s record cold has been linked to El Niño conditions in the tropical Pacific and a strongly negative North Atlantic Oscillation. The eruption of Iceland’s Laki volcano from June 8, 1783 to February [...]

In Brief: The last several centuries worth of ice accumulation on Greenland have distinct annual layers that enable researchers to evaluate interannual variability farther back than the period of instrumental records. Estimating how Earth’s climate varied before the modern period of instrumental records requires looking at natural records. How much a tree grows each year [...]

Some winters are colder than others and some winters are wetter and snowier than others. Trivia Question: What is the best way to predict what kind of winter you will have? a) Look at how intense the Sun is right now b) Look at how much ice there is in the Arctic c) Look at [...]

From Climate Central: The currents around the equator in the Pacific Ocean are cooler than average this year, which means we are experiencing the phenomenon known as La Niña. This oceanic and atmospheric cycle can bring good weather conditions, or poor ones, depending on where you live and your point of view. Climate Center: La [...]

Preliminary results indicate that on September 10, 2010, the Arctic sea ice reached its annual minimum extent of 1.84 million square miles. This is the third lowest extent on record after the 2008 and record low 2007 seasons, and 22 percent below the 1979-2009 average minimum. This year’s melt season started late, leading to the [...]

Warm ocean surface temperatures in the North Atlantic provide the warm and moist air that fuels hurricanes, which develop out of random disturbances in the tropics that provide the spark for these storms. Warmer waters in the North Atlantic generally mean more fuel for the storms. But did you know that surface temperature conditions in [...]

Over the past century, the Arctic was cooler than normal from 1900-1915, warmer than normal during the 20′s, 30′s and 40′s, cooler than normal during the 50′s, 60′s and 70′s and has been warmer than normal from the early 1980′s to today. Trivia Question: During warm periods in the Arctic, is the Antarctic generally: a)   [...]

In the Southwest U.S., prolonged dry episodes are defined as periods of two months or longer when daily precipitation falls below one millimeter. Trivia Question: Have such prolonged dry episodes become more or less common over the past 60 years? a)    More common b)    Less common c)    No change The correct answer is b. Despite [...]

Teleconnections occur when an event in one part of the world impacts another part of the world. One frequent source of teleconnections is the El Niño-Southern Oscillation (ENSO).  ENSO is the periodic shift in wind patterns and sea-surface temperatures over the tropical Pacific Ocean. ENSO’s teleconnections include control over the number of winter storms impacting [...]

Much of our weather in the United States depends on what is happening in the tropical Pacific Ocean. During an El Niño event, which is happening now, the eastern tropical Pacific is warmer than average. During La Niña events, the eastern tropical Pacific is cooler than average. While South America’s west coast may seem far [...]

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, [...]