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A tale of two climate scenarios. Last week, a team of researchers released new estimates of how the West Antarctic ice sheet could rapidly melt before 2100. The study predicts a sea-level rise of six feet within the next eight decades, much higher than previous consensus estimates. The melt would send the sea level soaring around the world, deluging nearly every coastal city. The New York Times connected the scientific finding to a political outcome, reporting that its findings entailed “a profound crisis within the lifetimes of children being born today.”

The week before, the former head of climate science at NASA, James Hansen, published his long-awaited study (with dozens of co-authors) on how more ice melt from the poles could dramatically shift global weather, creating hemispheric superstorms strong enough to toss up huge boulders from the ocean floor. The study’s methodology was unusual: Hansen and his team decided that current climate models didn’t account for sufficient melt, so they entered it by hand and watched what happened next. So many climate scientists privately disagreed with the study’s technique that the Associated Press declined to cover it. (As I wrote at The Atlantic, other outlets embraced its findings as canonical.)

But if the study was scientifically unusual, it was exceptional as politics. Hansen and his co-authors foresaw sea-level rise of “several meters”—certainly more than six feet—but then they mixed quantitative estimate with political prediction. “There is a possibility, a real danger, that we will hand young people and future generations a climate system that is practically out of their control,” they write in the paper’s conclusion.

Hansen’s study does feel like a change in how researchers communicate climatology: a new tendency toward science mixed with advocacy. Perhaps Hansen, by going so far out, will buy other researchers room to sketch the political consequences of climate change more concisely or guardedly. But watching the two studies enter the public sphere, I was struck by how much more dire the Antarctic scenario seemed. Hansen’s study, though terrifying, was structured as a news event and a provocation. The Antarctic study was quiet, dire science.

The Macro Trends

The atmosphere is filling with greenhouse gases. For the week beginning on March 20, 2016, the Mauna Loa Observatory measured 405.62 carbon-dioxide molecules per million in the atmosphere (ppm).

The year before, the Observatory observed 401.43 ppm the same week. In 2006, atmospheric carbon stood at 382.76 ppm for the final week of March.

Based on previous seasonal trends, atmospheric carbon will continue for another month or so before beginning to fall, as blooming plants in the North Hemisphere pull carbon out of the atmosphere. It’s looking increasingly like November 11, 2015, was the last day of our lifetimes with a daily carbon measurement below 400 ppm.

Renewable energy costs are falling quickly, as oil remains historically cheap. For the first time ever, the United States installed more solar than natural-gas capacity in 2015.

A professor at the University of Victoria proposes that oil remains cheap because Saudi Arabia is, in effect, shorting oil: Seeing that their fossil-fuel reserves exceed the planet’s carbon budget, the Saudis “appear to be positioning themselves for the next best option: gobbling up as much of the earth’s remaining carbon budget for themselves before the bubble bursts. Isn’t it better to sell at a lower price than to receive nothing at all from vast unburnable reserves?”

The Obama administration is trying to implement its first major greenhouse-gas-limiting regulations. The D.C. Circuit has scheduled oral argument on the case for June 2. Google, Apple, Microsoft, and Amazon filed an amicus brief supporting the Clean Power Plan with the court on Friday.

E&E Publishing has a good, state-by-state breakdown of How states are responding individually to the SCOTUS stay.

The Financial Times, citing nonprofit-collected data, say shareholders are forcing a record number of votes on climate-change-related issues, including whether ExxonMobil and Chevron should permit buybacks to avoid stranded assets.

China is planning a cap-and-trade program to limit carbon emissions. The country’s newest five-year plan, released earlier in March, orders a nearly 50 percent reduction in carbon intensity from 2005 levels. And the national government has blocked new coal plants from being built in 15 regions

Brad Plumer, at Vox, considers whether the country’s coal usage has peaked.

After Paris

It’s been 15 weeks since the 21st Conference of the Parties reached the Paris Agreement. Both the United States and China say they will sign the document on April 22 in New York.

This week in the Earth system

El Niño has now almost fully diminished, and the Pacific is now only three our four months away from returning to neutral status. The Australian Bureau of Meterology sees La Niña and a “neutral” Pacific as equally likely in the second half of the year.

Most of Earth's land surfaces were warmer than average or much warmer than average. … Overall, the six highest monthly temperature departures in the record have all occurred in the past six months. February 2016 also marks the 10th consecutive month a monthly global temperature record has been broken.

  • Since 2010, a U.S. state has set a new monthly warmth record 132 times times. In the same period, a state has set a new record for extreme cold four times. “The increase in extreme warmth and decrease in extreme cold is precisely what is expected in a warming world.”

  • About 40 percent of Russia’s food is imported, according to NPR. I got curious about how that compares to the U.S. It turns out that only 19 percent of America’s food is imported. But Russia also doesn’t have a warm Mediterranean climate, or really much of a temperate western coastal climate. In other words, it doesn’t have California, which accounts for between 12 and 16 percent of U.S. food production, depending on how you measure it.

  • “There are no perfect or correct seasons.” The director of the Royal Botanic Gardens in Melbourne, Australia, proposes splitting spring into two seasons—“sprinter,” a first wave of small flowering plants; and “sprummer,” a second wave. (Via @vruba.)


‘The Time To Act Is Now,’ Says Yellowing Climate Change Report Sitting In University Archive