Clouds need to condense around small particles called aerosols to form, and human aerosol pollution—primarily in the form of sulfuric acid—has made for cloudier skies. That’s why scientists have generally assumed Earth’s ancient skies were much sunnier than they are now. But today, three new studies show how naturally emitted gases from trees can also form the seed particles for clouds. The results not only point to a cloudier past, but they also indicate a potentially cooler future: If Earth’s climate is less sensitive to rising carbon dioxide (CO₂) levels, as the study suggests, future temperatures may not rise as quickly as predicted.

Each day in California an estimated 1.5 billion gallons (5.7 billion liters) of treated water are dumped into the ocean – that’s more than the amount of water needed to fill 2,270 Olympic-sized swimming pools. It’s the water that’s collected from the sinks, bathrooms and laundries in your home and delivered to municipal wastewater treatment facilities. But what if these billions of gallons of wastewater were further purified and put to use to help solve California’s water woes?

Last winter’s rain and snow didn’t come close to solving our water deficit, and we need to think outside the box.

Nervous investors, concerned about their nest eggs, will check the financial markets. Is the New York Stock Exchange up? What direction is the NASDAQ moving?

For people living in the American Southwest, water levels in reservoirs play the same role. And Lake Mead is the blue chip, the biggest, most consequential, most widely watched piece in the game. When water levels are up, spirits are unburdened. People are confident in their place in the desert.

Wedged between Arizona and Utah, less than 20 miles up river from the Grand Canyon, a soaring concrete wall nearly the height of two football fields blocks the flow of the Colorado River. There, at Glen Canyon Dam, the river is turned back on itself, drowning more than 200 miles of plasma-red gorges and replacing the Colorado’s free-spirited rapids with an immense lake of flat, still water called Lake Powell, the nation’s second largest reserve.