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Plants use the sun’s energy to turn carbon dioxide in the air into the organic matter, or carbohydrates, that make up their bodies. Each year, Earth’s land plants take about 123 petagrams (123,000,000,000,000,000 grams) of carbon out of the atmosphere. About the same amount of carbon is respirated back into the air, however, leading to [...]

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 [...]

In the air around us, there are tiny particles called aerosols. Aerosols include things like smoke, volcanic ash and mineral dust sent into the atmosphere by winds. Although these aerosols are usually too small to see, they affect the climate directly by scattering incoming sunlight as well as indirectly by affecting how clouds form. While [...]

Earth’s carbon dioxide (CO2) levels rose from about 315 parts per million in 1960 to around 390 parts per million today. CO2 levels vary from place to place around the globe, with urban areas generally having higher concentrations than surrounding rural areas. Levels also vary based on the time of day. In temperate zones, for [...]

Along America’s East Coast, blue mussels (Mytilus edulis) have traditionally been an important food source for larger species. They are also commercially farmed and even help improve water quality by filtering out pollutants as they feed. As recently as 50 years ago, blue mussels could be found as far south as the waters around Cape [...]

Plants use the sun’s energy to turn carbon dioxide (CO2) in the air into the organic matter, or carbohydrates, that make up their bodies. This process, known as photosynthesis, ultimately feeds the rest of the food chain, with grazers eating the plants and carnivores and omnivores eating the grazers. How much carbon land plants take [...]

While Lake Chad today covers an area of around 115-200 square miles, at the end of the last ice age (12,000 years ago), there was Lake Megachad, which covered an area as large as 154,000 square miles. Rivers flowing into the lake brought in sediments from the surrounding landscape, and the bodies of plankton growing [...]

Oceanic phytoplankton – microscopic organisms that use the sun’s energy to convert carbon and water into the sugars that make up their bodies – account for about half of the production of organic, or living, matter on Earth. These phytoplankton feed the zooplankton, which eventually feed the larger fishes that feed seabirds, marine mammals and [...]

Many of Earth’s great ice masses, which collectively form the cryosphere, are floating on ocean surfaces. There are three main collections of floating ice: the Arctic sea ice, the Antarctic ice shelves and the Antarctic sea ice. All three components have seasonal fluctuations, with the Antarctic sea ice showing the most dramatic differences between winter [...]

For about the past two million years, Earth’s climate system has been characterized by glacial cycles that last between 80,000 to 120,000 years. These cycles have long periods when the Earth cools and ice sheets build up to their maximums, followed by relatively short warming periods when the ice retreats and then “interglacial periods” like [...]

Without a steady supply of oxygen in the air around us, we would suffocate. Compared to other planets in our solar system, Earth’s concentration of oxygen in the atmosphere is exceptional. Of the air that goes into your lungs, 78 percent is nitrogen and 21 percent is oxygen. The remaining one percent is a combination [...]

The coral reefs around the 3,700 square mile Florida Keys National Marine Sanctuary provide habitat for 5,500 species as well nursing, feeding and breeding grounds that support a 20 million pound per year fishery. Water temperatures in the sanctuary fluctuate annually between about 68 and 86 degrees Fahrenheit. These waters, which reach their annual peak [...]

There is more energy in the Earth’s climate today than there was in 1950. This increase in energy exists in warmer air temperatures, less ice, more extreme rainfall events, warmer land surfaces and warmer rivers and lakes. The vast majority of the cumulative energy gain, however, is in the oceans. The upper 2300 feet of [...]

One of Earth’s most dramatic seasonal cycles is the waxing and waning of the sea ice that surrounds Antarctica, the driest, darkest and coldest continent. At its maximum extent at the end of the Southern Hemisphere winter in September, a 6.9 million square mile expanse of ice extends from Antarctica’s shores out into the Southern [...]

Since the 1750′s, the amount of methane (CH4) in the atmosphere has increased by 250 percent. Much of this methane is emitted from lakes in northern regions. Glacial movement across the far North (north of 45 degrees) during the last ice age leveled the landscape, carved depressions in the bedrock and deposited ice that formed [...]

Earth 13,000 years ago was in the process of thawing from the coldest part of the last ice age. Then, something sudden and catastrophic happened: within a few decades, northern Europe’s average temperature dropped by 18 degrees Fahrenheit. The sudden cold period that followed is called the Younger Dryas, named after the Arctic tundra wildflower [...]

In northern China, how much rain falls each year is controlled by the strength of the Asian Monsoon – the system of seasonal winds that bring moist marine air onto land during the summer and cold dry air out to sea during the winter. When the monsoon system is strong, there is ample rainfall and [...]

Each year, rivers originating in the surrounding mountains and forests send an average of 229 trillion gallons of freshwater into the Gulf of Alaska. The amount of water flowing into the Gulf and when most of the flow occurs affects how salty the waters in the Gulf are. How salty these waters are affects the [...]

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 [...]

Glaciers have a mass balance. Glaciers lose mass by melting during the warm season (primarily the summer months) and gain mass by accumulating snow during the cold season (centered around the winter months). If a glacier accumulates more mass during the cold season than it loses during the warm season, it is said to have [...]