The Docket | Emerging Science

The Water Year

What the Snow Isn't Delivering

By Maya Jiménez— May 19, 2026

Feature image for article: What the Snow Isn't Delivering

Water Year 2026 precipitation across the Upper Colorado Basin is 82 percent of normal. Forecasted inflow to Lake Powell is 34 percent. The gap is warming, pulling moisture from soil and snowpack before it ever reaches the river. In western Colorado's Grand Valley, growers are deciding row by row which orchards to water and which to sacrifice. The arithmetic that governs 40 million people downstream is being rewritten by physics, and the reservoirs are recording the answer.

The Water Year

What the Snow Isn't Delivering

By Maya Jiménez— May 19, 2026

Water Year 2026 precipitation across the Upper Colorado Basin is 82 percent of normal. Forecasted inflow to Lake Powell is 34 percent. The gap is warming, pulling moisture from soil and snowpack before it ever reaches the river. In western Colorado's Grand Valley, growers are deciding row by row which orchards to water and which to sacrifice. The arithmetic that governs 40 million people downstream is being rewritten by physics, and the reservoirs are recording the answer.

Water Signals

Four findings from the past year, four different research teams, one shared physical system: water.

Ocean heat loads the atmosphere with vapor. Acceleration compresses every timeline built around how that water gets stored and moved. Drought-killed forests stop recycling moisture into downwind rain. And the tipping points nearest to triggering are, overwhelmingly, thresholds in how water behaves on a planetary scale. The connections here are hydrological, not thematic. The plumbing underneath every water decision is being rewritten faster than the engineering specs assumed.

Water Signals

Four findings from the past year, four different research teams, one shared physical system: water.

Ocean heat loads the atmosphere with vapor. Acceleration compresses every timeline built around how that water gets stored and moved. Drought-killed forests stop recycling moisture into downwind rain. And the tipping points nearest to triggering are, overwhelmingly, thresholds in how water behaves on a planetary scale. The connections here are hydrological, not thematic. The plumbing underneath every water decision is being rewritten faster than the engineering specs assumed.

Ocean Heat

Record Ocean Heat Rewrites Where Water Goes

Oceans absorbed 23 zettajoules of extra heat in 2025, a ninth straight record. Warmer surfaces pump more moisture into the atmosphere, fueling heavier storms. But in the Sierras and Rockies, that moisture increasingly falls as rain, not snow. Less snowpack means less slow-release summer water for the cities and irrigators downstream counting on it.

Warming Rate

Your Reservoir's Forecast Assumed Slower Warming

Warming has accelerated to roughly 0.35°C per decade since 2015, about 75% faster than the prior trend. Foster and Rahmstorf put 1.5°C before 2030. Every reservoir projection, every drought model, every aquifer drawdown timeline in active use was calibrated to the old pace. The leading explanation, reduced shipping aerosols unmasking trapped heat, remains probable but unsettled.

Carbon Sinks

Drought Burned the Planet's Carbon Safety Net

Global forests absorbed only a quarter of their usual carbon in 2023–2024, per WRI analysis. The feedback is vicious: drought weakens trees, weakened trees burn, burning releases stored carbon, released carbon accelerates warming. The same drying that drains reservoirs is gutting the system that was supposed to slow the warming down.

Tipping Points

Water Systems Hold the Nearest Tipping Points

A 2026 review identifies up to eight tipping points reachable below 2°C. The ones closest to triggering are water systems: ice sheet collapse locking in meters of sea-level rise, Amazon dieback disrupting rainfall across South America, permafrost thaw releasing carbon and rewriting Arctic hydrology. Once crossed, these thresholds don't offer a return trip.

The Research

Ocean Heat Content Sets Another Record in 2025

The ocean absorbed another 23 zettajoules of heat in 2025, a ninth straight record. Warming rates have more than doubled since 2005. Because oceans absorb over 90% of excess planetary heat, every coastal flood baseline just shifted upward again.

Who gets hit first?

Every coastal infrastructure project, from Houston's Ike Dike to Miami's stormwater system, was engineered to a sea-level number this study just obsoleted.

How solid is this?

Over 50 scientists across 31 institutions, cross-validated against independent ocean observing systems in Asia, Europe, and North America.

Global Warming Has Accelerated Significantly

Strip out El Niño, volcanic eruptions, and solar cycles from five major temperature datasets and the underlying trend since 2015 is roughly 0.36°C per decade, double the late-20th-century rate. Sustained, that puts 1.5°C arrival before 2030. The cause remains genuinely contested.

Why does the rate matter?

Aquifer depletion schedules, snowpack projections, reservoir evaporation models were all calibrated to a slower warming rate that no longer holds.

Is this settled?

Michael Mann attributes more to natural variability; a UC Santa Cruz team found no detectable acceleration without the signal-filtering method Foster and Rahmstorf use.

The Implications of Overshooting 1.5°C on Earth System Tipping Elements

Up to eight Earth system tipping points could trigger below 2°C of warming. At 1.4°C today, warm-water coral reefs have likely already crossed theirs. Ice sheets, permafrost, and the Amazon face tipping risks that interact in ways researchers still can't fully model.

Where's the water?

Greenland's ice sheet holds three meters of sea-level rise; Amazon dieback cuts continental rainfall; thawing permafrost rewrites Arctic hydrology from the ground up.

What don't we know?

Cascade effects between tipping elements remain poorly characterized, meaning compound risk across interacting systems may be systematically underestimated.

10 New Insights in Climate Science 2025/2026

A synthesis of 70+ researchers finds the global land carbon sink shrank by more than a quarter in 2023. Separately, data from 170,000+ wells across 40 countries shows groundwater depletion speeding up, with nearly half of declining aquifers draining faster than in previous decades.

Why both at once?

Forests, soils, and aquifers are losing absorptive capacity simultaneously, compounding pressure on every local water budget from both directions.

Who stands behind this?

Future Earth, The Earth League, and the World Climate Research Programme, with over 150 expert reviewers across disciplines.

The Research

Ocean Heat Content Sets Another Record in 2025

The ocean absorbed another 23 zettajoules of heat in 2025, a ninth straight record. Warming rates have more than doubled since 2005. Because oceans absorb over 90% of excess planetary heat, every coastal flood baseline just shifted upward again.

Who gets hit first?

Every coastal infrastructure project, from Houston's Ike Dike to Miami's stormwater system, was engineered to a sea-level number this study just obsoleted.

How solid is this?

Over 50 scientists across 31 institutions, cross-validated against independent ocean observing systems in Asia, Europe, and North America.

The Research

Global Warming Has Accelerated Significantly

Strip out El Niño, volcanic eruptions, and solar cycles from five major temperature datasets and the underlying trend since 2015 is roughly 0.36°C per decade, double the late-20th-century rate. Sustained, that puts 1.5°C arrival before 2030. The cause remains genuinely contested.

Why does the rate matter?

Aquifer depletion schedules, snowpack projections, reservoir evaporation models were all calibrated to a slower warming rate that no longer holds.

Is this settled?

Michael Mann attributes more to natural variability; a UC Santa Cruz team found no detectable acceleration without the signal-filtering method Foster and Rahmstorf use.

The Research

The Implications of Overshooting 1.5°C on Earth System Tipping Elements

Up to eight Earth system tipping points could trigger below 2°C of warming. At 1.4°C today, warm-water coral reefs have likely already crossed theirs. Ice sheets, permafrost, and the Amazon face tipping risks that interact in ways researchers still can't fully model.

Where's the water?

Greenland's ice sheet holds three meters of sea-level rise; Amazon dieback cuts continental rainfall; thawing permafrost rewrites Arctic hydrology from the ground up.

What don't we know?

Cascade effects between tipping elements remain poorly characterized, meaning compound risk across interacting systems may be systematically underestimated.

The Research

10 New Insights in Climate Science 2025/2026

A synthesis of 70+ researchers finds the global land carbon sink shrank by more than a quarter in 2023. Separately, data from 170,000+ wells across 40 countries shows groundwater depletion speeding up, with nearly half of declining aquifers draining faster than in previous decades.

Why both at once?

Forests, soils, and aquifers are losing absorptive capacity simultaneously, compounding pressure on every local water budget from both directions.

Who stands behind this?

Future Earth, The Earth League, and the World Climate Research Programme, with over 150 expert reviewers across disciplines.

The Power Threshold

Hoover Dam Sits 20 Feet Above the Threshold Where 12 of Its 17 Turbines Go Dark

Lake Mead is roughly 30% full at 1,055 feet. Another 20-foot drop shuts down twelve of seventeen turbines, and output falls from an already diminished 500-600 megawatts to around 300. The Bureau of Reclamation projects this could happen by fall, after cutting releases from Lake Powell to keep that upstream reservoir alive.

Salt River Project shrugs. Hoover covers half a percent of its load. But Lincoln County Power District No. 1 in rural Nevada draws 70% of its electricity from the dam, serving about 2,000 agricultural customers. General manager Dane Bradfield has been plain about it: replacement power from the open market costs more, and those costs land directly on his ratepayers.

The Power Threshold

Hoover Dam Sits 20 Feet Above the Threshold Where 12 of Its 17 Turbines Go Dark

Lake Mead is roughly 30% full at 1,055 feet. Another 20-foot drop shuts down twelve of seventeen turbines, and output falls from an already diminished 500-600 megawatts to around 300. The Bureau of Reclamation projects this could happen by fall, after cutting releases from Lake Powell to keep that upstream reservoir alive.

Salt River Project shrugs. Hoover covers half a percent of its load. But Lincoln County Power District No. 1 in rural Nevada draws 70% of its electricity from the dam, serving about 2,000 agricultural customers. General manager Dane Bradfield has been plain about it: replacement power from the open market costs more, and those costs land directly on his ratepayers.

Tribal exposure:

At least fourteen tribal nations hold Hoover power contracts, including Navajo Tribal Utility Authority and Hualapai Tribe, with few alternative sources nearby

Grid timing:

Hoover ramps on demand to cover the evening spike when solar drops and air conditioners keep running. No battery system replaces that flexibility yet

Compound squeeze:

Metropolitan Water District uses Hoover power to pump the Colorado River Aqueduct. Less water and costlier electricity to move it, same shrinking lake

Peak pricing:

Replacement megawatts must be purchased during summer demand peaks, when wholesale electricity across the Western grid costs the most

Dead pool:

Below 950 feet, generation stops entirely. Below 895, water no longer flows through the dam by gravity. Both numbers used to feel theoretical