Outside my lab near Donner Pass in the Sierra Nevada mountains of California, new animal tracks are on the snow after a winter of hibernation, bird songs are lofting through the air, and the creek is flowing strongly with water from the melting snow. Spring has come worryingly early to the Sierra Nevada.

This past week, I joined teams of other scientists gathering the most important measurements of the Sierra Nevada snowpack from over 265 sites throughout the state. Typically, this measurement marks the transition from snow accumulation season to the melt season and contains the most snow of any measurement throughout the year. The 2022 results, however, confirmed what those of us monitoring the state’s drought had feared: California’s snowpack is now at 39 percent of its average, or 23 percent lower than at the same point last year. This signals a deepening of the drought — already the worst in the western United States in 1,200 years — and another potentially catastrophic fire season for much of the West.

Many people have a rather simplistic view of drought as a lack of rain and snow. That’s accurate — to an extent. What it doesn’t account for is human activity and climate change that are now dramatically affecting the available water and its management. As more frequent and large wildfires and extended dry periods batter the land, our most important tools for managing water are becoming less and less accurate. At the same time, our reliance on these models to try to make the most of the little water we have is becoming more and more problematic.

Droughts may last for several years or even over a decade with varying degrees of severity. During these types of extended droughts, soil can become so dry that it soaks up all new water, which reduces runoff to streams and reservoirs. Soil can also become so dry that the surface becomes hard and repels water, which can cause rainwater to pour off the land quickly and cause flooding. This means we no longer can rely on relatively short periods of rain or snow to completely relieve drought conditions the way we did with past droughts.

Many storms with near record-breaking amounts of rain or snow would be required in a single year to make a significant dent in drought conditions. October was the second snowiest and December was the snowiest month on record at the snow lab since 1970 thanks to two atmospheric rivers that hit California. But the exceptionally dry November and January to March periods have left us with another year of below average snowpack, rain and runoff conditions.

This type of feast-or-famine winter with big storms and long, severe dry periods is expected to increase as climate change continues. As a result, we’ll need multiple above-average rain and snow years to make up the difference rather than consecutive large events in a single year.

Even with normal or above-average precipitation years, changes to the land surface present another complication. Massive wildfires, such as those that we’ve seen in the Sierra Nevada and Rocky Mountains in recent years, cause distinct changes in the way that snow melts and that water, including rain, runs off the landscape. The loss of forest canopy from fires can result in greater wind speeds and temperatures, which increase evaporation and decrease the amount of snow water reaching reservoirs.

Similar to extended drought, fire also alters soil properties and can create flash flooding during intense periods of rain. These landscape changes, feast-or-famine precipitation patterns and increased demand on the water supply are making water management in the West a precarious and difficult task.

One of the most important tools for managing water during periods of drought are the models developed by various state and federal agencies such as the National Weather Service’s Office of Hydrologic Development, the Army Corps of Engineers and the California Department of Water Resources. Yet these models suffer from the same simplistic view of drought and water, and they are in dire need of an update.

Land surfaces, snow melt patterns and the climate have all changed since many of these models were developed, which means they’re missing crucial pieces of today’s water puzzle. What’s prevented updates to the models for decades is shrinking funding for science and engineering.

Models may not be able to reliably inform water managers how much rain and snow will run off the land into reservoirs, which can mean severe shortages in a worst-case scenario. Given the shrinking reservoir levels and meager snowpacks of recent years, discrepancies between the water expected and that which arrives could mean the difference between having water in the taps or entire towns running dry.

We are looking down the barrel of a loaded gun with our water resources in the West. Rather than investing in body armor, we’ve been hoping that the trigger won’t be pulled. The current water monitoring and modeling strategies aren’t sufficient to support the increasing number of people that need water. I’m worried about the next week, month, year, and about new problems that we’ll inevitably face as climate change continues and water becomes more unpredictable.

It’s time for policymakers who allocate funding to invest in updating our water models rather than maintaining the status quo and hoping for the best. Large-scale investment in the agencies that maintain and develop these models is paramount to preparing for the future of water in the West.

Better water models ultimately mean more accurate management of water, and that will lead to greater water security and availability for the millions of people who now depend on the changing water supply. It is an investment in our future and, further, an investment in our continued ability to inhabit the water-scarce regions in the West. It’s the only way to ensure that we’re prepared when the trigger is pulled.

5 Takeaways From the New U.N. Report on Limiting Global Warming.

Without swift action, we are headed for trouble.

The report makes it clear: Nations’ current pledges to curb greenhouse-gas emissions most likely will not stop global warming from exceeding 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, within the next few decades. And that’s assuming countries follow through. If they don’t, even more warming is in store.

That target — to prevent the average global temperature from increasing by 1.5 degrees Celsius over preindustrial levels — is one many world governments have agreed to pursue. It sounds modest. But that number represents a host of sweeping changes that occur as greenhouse gases trap more heat on the planet’s surface, including deadlier storms, more intense heat waves, rising seas and extra strain on crops. Earth has already warmed about 1.1 degrees Celsius on average since the 19th century.

Emissions are tied to economic growth and income.

So far, the world isn’t becoming more energy-efficient quickly enough to balance out continued growth in global economic activity, the report says.

Carbon dioxide emissions from factories, cities, buildings, farms and vehicles increased in the 2010s, outweighing the benefits from power plants’ switching to natural gas from coal and using more renewable sources such as wind and solar.

On the whole, it is the richest people and wealthiest nations that are heating up the planet. Worldwide, the richest 10 percent of households are responsible for between a third to nearly half of all greenhouse gas emissions, according to the report. The poorest 50 percent of households contribute around 15 percent of emissions.

Clean energy has become more affordable.

The prices of solar and wind energy, and electric vehicle batteries, have dropped significantly since 2010, the report finds. The result is that it may now be “more expensive” in some cases to maintain highly polluting energy systems than to switch to clean sources, the report says.

In 2020, solar and wind provided close to 10 percent of the world’s electricity. Average worldwide emissions grew much more slowly in the 2010s than they did in the 2000s, partly because of greater use of green energy.

It wasn’t obvious to scientists that this would happen so swiftly. In a 2011 report on renewables, the same panel noted that technological advances would probably make green energy cheaper, though it said it was hard to predict how much.

Still, altering the climate path won’t be easy or cheap.

The world needs to invest three to six times more than it’s currently spending on mitigating climate change if it wants to limit global warming to 1.5 or 2 degrees Celsius, the report says. Money is particularly short in poorer countries, which need trillions of dollars of investment each year this decade.

As nations drop fossil fuels, some economic disruption is inevitable, the report notes. Resources will be left in the ground unburned; mines and power plants will become financially unviable. The economic impact could be in the trillions of dollars, the report says.

Even so, simply keeping planned and existing fossil-fuel infrastructure up and running will pump enough carbon dioxide into the atmosphere to make it impossible to keep warming below 1.5 degrees, the report says.

There are other steps that could help and wouldn’t break the bank.

The report looks at a host of other changes to societies that could reduce emissions, including more energy-efficient buildings, more recycling and more white-collar work going remote and virtual.

These changes do not have to be economy-dampening chores, the report emphasizes. Some, like better public transit and more walkable urban areas, have benefits for air pollution and overall well-being, said Joyashree Roy, an economist at the Asian Institute of Technology in Bangkok who contributed to the report. “People are demanding more healthy cities and greener cities,” she said.

In all, steps that would cost less than $100 per ton of carbon dioxide saved could lower global emissions to about half the 2019 level by 2030, the report says. Other steps remain pricier, such as capturing more of the carbon dioxide from the gases that pour from smokestacks at power plants, the report says.

The world also needs to remove carbon dioxide that is already in the atmosphere. Planting more trees is pretty much the only way this is being done at large scale right now, the report says. Other methods, like using chemicals to extract atmospheric carbon or adding nutrients to the oceans to stimulate photosynthesis in tiny marine plants, are still in early development.

“We cannot ignore how much technology can help,” said Joni Jupesta, an author of the report with the Research Institute of Innovative Technology for the Earth in Kyoto, Japan. “Not every country has a lot of natural resources.”

Understand the Latest News on Climate Change

Deadly combination. Global warming is greatly increasing the risk that extreme wildfires in the American West will be followed by heavy rainfall, a new study has found, highlighting the need to be prepared for mudslides and flash floods after the flames from severe blazes are out.

Ice shelf collapses. For the first time since satellites began observing Antarctica nearly half a century ago, an ice shelf has collapsed on the eastern part of the continent. The 450-square-mile ice shelf was located in an area known as Wilkes Land; the loss occurred in mid-March.

A massive leak. Startlingly large amounts of methane are leaking from wells and pipelines in New Mexico’s Permian Basin, according to a new analysis of aerial data, suggesting that the oil and gas industry may be contributing more to climate change than was previously known.

Australia’s Great Barrier Reef. A wide stretch of the Great Barrier Reef has been hit by a sixth mass bleaching event, an alarming indicator that the area is under intense stress from the waters around them, which have been growing steadily warmer as a result of climate change..

Enduring drought. Drought conditions are likely to continue across more than half of the continental United States through at least June, the National Oceanic and Atmospheric Administration said. Nearly 60 percent of the continental United States is experiencing drought.