Arizona, California and Nevada on Monday proposed a deal to significantly cut their water use from the drought-stricken Colorado River over the next three years. The $1.2 billion proposal is a potential breakthrough in a stalemate over how to deal with a rising problem that pitted Western states against one another. The plan would conserve an additional 3 million acre-feet of water from the 1,450-mile river that provides water to 40 million people in seven U.S. states, parts of Mexico and more than two dozen Native American tribes. Cities, irrigation districts and Native American tribes in the three states will receive federal funding in exchange for temporarily using less water.

South Korea will send a 21-member team of government experts to Japan next week to visit the Fukushima nuclear power plant where they will review contentious Japanese plans to release treated but slightly radioactive water into the sea. Officials said the six-day visit starting Sunday will focus on examining the plant’s processing system, which reduces radioactive materials from contaminated water, and whether the treated water would be safe enough to be diluted and discharged into the ocean. The safety of the water for years has been a sensitive issue between the U.S. allies, who are now working to repair long-strained ties to address joint challenges like the North Korean nuclear threat and China’s assertive foreign policy.

The United Nations' weather agency says there's a two-out-of-three chance that the world will reach the internationally accepted global temperature threshold for limiting the worst effects of climate change sometime in the next five years. But scientists say it's likely to be a fleeting flirtation with that danger point of 1.5 degrees Celsius. That's because they expect a temporary burst of heat from a looming El Nino will supercharge the warming underway from humans burning coal, oil and gas. They say it's likely to slip back after the El Nino fades. But they are concerned that even temporary breaches of the threshold could happen with more frequency.

The Environmental Protection Agency is strengthening a rule aimed at controlling and cleaning up toxic waste from coal-fired power plants. A proposal Wednesday would require safe management of coal ash dumped in hundreds of older landfills, “legacy” ponds and other inactive sites that currently are unregulated at the federal level. EPA Administrator Michael Regan said the plan would hold polluters accountable for controlling and cleaning up coal ash, a byproduct of burning coal that can pollute groundwater, drinking water and air and has been linked to cancer and other health problems. The plan follows an EPA proposal last week to impose new limits on greenhouse gas emissions from coal- and gas-fired power plants.

A federal appeals court has ruled that the Environmental Protection Agency must regulate perchlorate, reversing a rollback the agency first made under then-President Donald Trump. Perchlorate is used in munitions, fireworks and matches, but when it contaminates drinking water it can lead to brain damage in infants and breastfeeding children. The EPA first announced it would regulate it in 2011, when the Obama administration said the chemical contaminates the water of as many as 16 million Americans. The Trump-era EPA backed off that plan in 2020, saying that perchlorate was occurring at lower levels than previously thought. But one of the appellate judges said that was based on a “biased dataset that was selectively updated.”

Scientists now fear increasingly warmer water in daily tides are doing much more damage to one of Greenland's glaciers than they thought. A study published Monday examined the Petermann glacier in far northwestern Greenland. Warmer water from climate change is eating a large hole deep inside the glacier and accelerating ice loss at its key connection point with the ocean floor. The hole is bigger than the Washington Monument. Researchers say if this is happening on the rest of the world's ice sheets, global ice loss and sea level rise could be twice as fast as previously thought.