A satellite view of a harmful algae bloom on Lake Erie in October 2011. (NASA Earth Observatory) A two-day ban on drinking water has been lifted in Toledo, Ohio. But the toxic algae bloom that led to the ban is still floating around Lake Erie and ones like it could become more common as the climate continues to change in a warming world. Nutrients in agricultural runoff is the biggest contributor to algae blooms in Lake Erie. What brings that...

It's the size of Connecticut, and it's suffocating everything in sight. Called the Gulf of Mexico dead zone, it's a stretch of water low in oxygen off the coasts of Louisiana and Texas, according to the National Oceanic and Atmospheric Administration. Scientists map the area every year to track the changes in its size, and during a recent survey cruise, they found this summer's dead zone measures 5,052 square miles, the report added. West of the Mississippi River, a dead...

Despite receiving a series of thunderstorms in recent weeks, some of which have dropped rains heavy enough to trigger mudflows in some areas, California remains locked in the grip of a historic drought that shows no signs of abating anytime soon. The storms' overall effect on the state's drought has been "inconsequential," according to the U.S. Drought Monitor in its most recent report on the state of drought across the country. While they reduced irrigation demands for some crops and...

In the West, Colorado is known as a “headwaters” state because most of the region’s biggest rivers begin in the Colorado Rocky Mountains. The Colorado River. The Arkansas River. The Rio Grande. The San Juan River. The Platte River —North and South. Altogether, they provide19 stateswith drinking and irrigation water, including the cities of Los Angeles, Phoenix and Denver, among many others. All of the water in those rivers comes from one source: the Rocky Mountains’ snowpack, which is expected...

A harmful algae bloom 1.5 times the size of Rhode Island is heading toward Florida's Gulf Coast. Elevated concentrations of Karenia brevis, the harmful organism that makes up "red tide," were reported 20 miles off the coast of Florida in the Gulf of Mexico, according to the Florida Fish and Wildlife Conservation Commission (FWC). According to satellite imagery estimates, the algae bloom is up to 60 miles wide and 90 miles long, Florida's biggest bloom since 2005. "They are part...

From Alaska to the Alps, photos oftoday’s diminished glacierscontrasted with grainy black-and-white images of their former, more massive states are some of the most widely used examples of the impact of human-caused climate change, with their melt threatening water supplies,enhancing sea level rise, and posing threats like floods from bursting glacial lakes. “Everybody is using [these photos],” saidBen Marzeion, a climate scientist with the University of Innsbruck in Austria. “But nobody actually looked at whether it’s justified to do this.”...

The western end of Lake Erie now has a greenish tint, recent satellite images show. Close-ups show the area between northwest Ohio, southeast Michigan and the far southwestern portion of Ontario. When heavy rains hit, municipal sewer systems are often overwhelmed, dumping a mix of storm water and untreated sewage into nearby waterways. It's a nationwide problem — an estimated 775 communities in the United States have sewer systems constructed this way, with combined sewage and storm water pipes, including...

Stream flows are changing in major ways along the Missouri River thanks in large part to climate change, and those shifts are having big impacts on thousands of farmers, businesses, vacationers and others who depend on it. The news comes in a U.S. Geological Survey study published in late July, which examined stream flow data from more than 200 streamgages up and down the Missouri between 1960 and 2011. Nearly half of the streamgages surveyed showed that flows had increased...

As the sea ice covering the Arctic continues to shrink under the influence of greenhouse gas-induced warming,it’s causing a host of other changes in the region, including the growth of large waves in the previously iced-over areas. Those waves could potentially reinforce and hasten the demise of sea ice, leading to further changes in the fragile polar realm. Changes brought on by global warming in the Arctic region have been well documented. Temperatures there have risen twice as fast as...

Emerald Bay lies under blue skies at Lake Tahoe on July 23, 2014, near South Lake Tahoe, California. The area is being challenged by drought, invasive species, the threat of catastrophic wildfire and climate change. (Sean Gallup/Getty Images) Visited by millions of tourists every year, Lake Tahoe's future as one of the West's premier destinations is under threat from drought, invasive species, out-of-control wildfires and the long-term challenges of climate change, state and congressional officials said Tuesday. The warning was...

Cities are almost always hotter than the surrounding rural area but global warming takes that heat and makes it worse. In the future, this combination of urbanization and climate change could raise urban temperatures to levels that threaten human health, strain energy resources, and compromise economic productivity. Summers in the U.S. have been warming since 1970. But on average across the country cities are even hotter, and have been getting hotter faster than adjacent rural areas. Urban heat measured by...

Strong waves crash against rocks in southwestern France during high tide on the Atlantic Ocean in February 2014. A recent study suggests that the global warming slowdown of the past 15 years may be due to heat 'hiding' deep in the Atlantic. (GAIZKA IROZ/AFP/Getty Images) Global warming accelerated rapidly from the 1970s through the 1990s but abruptly slowed down after that, and exactly why has been a puzzle climate scientists have been trying to solve ever since. This pause or...