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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 [...]

The Great Salt Lake is a prominent feature of the Intermountain West landscape. Geologists who study the region believe that the size of the lake varies on long time scales. Trivia Question: 20,000 years ago, when Earth’s climate was much cooler and a massive ice sheet extended form the Arctic south all the way to [...]

As the Earth warms, a few things happen to the water cycle. Warmer temperatures mean more evaporation from the soil, which can cause land surfaces to dry. They also mean, however, that the air holds more moisture, which can lead to more rainfall in certain regions. The polar regions, for example, are wetter than they [...]

In Brief: African aerosols are transported across the Atlantic, affecting the climate of the Amazon rainforest. Dust suspended in the air and smoke from fires make up most of the aerosol concentrations found in the air around us. Aerosols affect how much sunlight reaches the Earth’s surface and how clouds form, which means they can [...]

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: Glaciers, a key source of water in the West, are melting more in the summer than they are growing during the winter. The glaciers that make the peaks of the Western United States white year round are located almost exclusively within National Forests and National Parks. In addition to providing scenery and tourist [...]

Yellowstone, America’s first established National Park, has changed as average annual temperatures have warmed by one degree Fahrenheit over the last 40 years. This warming trend has been accompanied by a slight decrease in annual rainfall levels. Related changes include: Tree Cover: As temperatures have warmed since 1970, tree cover in areas that had not [...]

Trivia Question: True or False: Bacteria can cause rainfall. The correct answer is true. Bacteria are single-celled organisms that are found on every continent, at the bottom of the ocean and as high as 50 miles in the atmosphere. Each year, between 90 million and four billion pounds of bacteria travel from the Earth’s surface [...]

In Brief: Forest species composition is influenced by decadal rainfall trends as well as short-lived disturbance events, like El Niño induced droughts. Forests react to climate change through changes in species composition. The biodiversity, or collection of different species with different strengths and vulnerabilities, of a forest enables it to adapt to changing conditions. For [...]

In Brief: In the eastern United States, afternoon summertime rainfall events are more probable in areas where soil moisture levels are high. Afternoon summertime precipitation in the wet, humid and heavily vegetated eastern United States is related to the evaporation that happens in the morning. Lots of soil moisture can stimulate lots of evaporation, which [...]

In Brief: The boundaries of the Hadley circulation have expanded over the past 30 years, with the most pronounced expansions occurring during the summer months. Earth’s weather is driven largely by the behavior of two large scale tropical circulation systems: the Hadley circulation and the Walker circulation. The Hadley circulation develops as large columns of [...]

In Brief: Earth’s Walker circulations have strengthened over the last 30 years, with wet regions of the circulations getting wetter and dry regions getting drier. Earth’s weather is driven largely by the behavior of two large scale tropical circulation systems: the Hadley circulation and the Walker circulation. The Walker circulation can be broken down into [...]

In Brief: Climate is the dominant force behind changes in river flow on a global scale, despite many other significant contributing factors that must be accounted for when making accurate estimates of water cycle changes. Regional precipitation and temperature changes, atmospheric composition changes that affect plant growth, land use changes, changes in nitrogen deposition on [...]

In Brief: Sunlight reflecting off snow covered forest floors gives extra energy to boreal forest trees as they come out of their winter dormancy. Boreal (Northern Hemisphere) spring is here. Even in the high northern latitudes, temperatures are beginning to warm and plants are beginning to come out of dormancy and photosynthesize, using the Sun’s [...]

In Brief: Glaciers in northeastern Utah’s Uinta Mountains began their retreat a few thousand years after the Laurentide Ice Sheet, illustrating the importance of both the position of the jet stream and local moisture sources for glacial dynamics. About 100 miles east of Salt Lake City, the Uinta Mountains of northeastern Utah rise up out [...]

Temperatures are dropping and the onset of the Northern Hemisphere snow season is upon us. In the Arctic region, snow is already beginning to fall and over the next few weeks, other high latitude and even some mid-latitude locations will get their first dusting. The full snow season is defined as the interval between the [...]

Earth Gauge Video is available for this tip. In Brief: Temperatures in local waterways are rising from a combination of factors. Moving from Chicago to Baltimore, where the average temperature is about ten degrees Fahrenheit warmer, might take a little bit of adjustment but almost certainly wouldn’t be fatal for humans. Most fish and other [...]

The term cloud condensation nuclei (CCN) is a fancy way of describing the tiny particles that even smaller water vapor droplets cling to as raindrops form. Once enough water vapor droplets gather on the nuclei, raindrops fall. This is a critical part of Earth’s water cycle, which moves water from the oceans to the land, [...]

The area around Vermont’s Green Mountains is a “transition zone” between the boreal forests in Canada, which are dominated by conifer species that are better adapted to the extreme winter cold, and the broadleaf forests that are familiar to residents of the eastern U.S. Higher elevation areas of the Green Mountains are significantly colder and [...]

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 [...]