Last time there was this much CO2 in the atmosphere was 3 million years ago, in the Pliocene era. What can that tell us about what we're in for? The world will probably keep warming. Sea levels will probably keep rising. Ice sheets will probably keep melting. Saber-tooth tigers? NOT OUT OF THE QUESTION. Okay, probably out of the question.  

Thousands of young climate activists descended on Washington, D.C., over the weekend for the third biennial Power Shift conference. Then on Monday they took their message to the streets and the president's doorstep. Check out these photos by Jay Mallin to get a sense of what went down. Photo: Jay Mallin The Power Shift crowd protests outside the White House on Monday. On Friday, a few of the activists got to take their message inside the White House and meet with President Obama.

Tomorrow, the Supreme Court is set to rule on American Electric Power vs. Connecticut, a case where the state of Connecticut is suing a power company for contributing to global warming. Trying to research the legal details of this case is making me cry, so I hope you people appreciate the following bullet points, which will hopefully spare you having to do the same: At issue, big picture: Can states and private entities sue utilities for contributing to climate change? At issue, smaller pictures: Do states and private entities have a leg to stand on when complaining about climate change? …

Bill McKibben gave a fiery speech to young climate activists Saturday night at Power Shift 2011. Here's the video and transcript: All right, listen up. Very few people can ever say that they are in the single most important place they could possibly be, doing the single most important thing they could possibly be doing. That's you, here, now. You are the movement that we need if we are going to win in the few years that we have. You have the skills now. You are making the connections. And there is no one else. It is you. That is …

Matthew Nisbet's conclusions don't match his own report's data.Professor Matthew Nisbet of American University has written an error-riddled, self-contradictory, demonstrably false report, "Climate Shift: Clear Vision for the Next Decade of Public Debate" [PDF]. The 99-page report's two central, but ridiculous, claims are: The environmental movement outspent opponents during the climate bill debate. Media coverage of climate change has become balanced and was not a factor in the defeat of the cap-and-trade bill. The report makes these untenable claims in order to shift the blame for the bill's failure to climate scientists, environmentalists, foundations, and most especially Al Gore. None …

The Earth may look glum, but it's not to be messed with.Photo: John LeGearThis essay was originally published on TomDispatch and is republished here with Tom's kind permission. In his 2010 book Eaarth: Making a Life on a Tough New Planet, environmental scholar and activist Bill McKibben writes of a planet so devastated by global warming that it's no longer recognizable as the Earth we once inhabited. This is a planet, he predicts, of "melting poles and dying forests and a heaving, corrosive sea, raked by winds, strafed by storms, scorched by heat." Altered as it is from the world …

(click to embiggen) Look, not everyone's motivated by the threat of extreme weather events, rising sea levels, and threatened habitats. But nobody likes warm beer. Use this chart to put climate change in perspective for the beer guzzler in your life. (Note: Will not work in Britain.)

Mitch Daniels takes on the "climate change theocracy"Photo: Indiana Public MediaIndiana Gov. Mitch Daniels says he'll decide by April 29 whether to run for the Republican presidential nomination. While he's pondering his prospects, let us ponder his views on climate change. Turns out they're a lot weirder than you thought. It's well-known that Daniels has voiced skepticism about climate science and bashed cap-and-trade. But in a little-noticed May 2009 speech, he went further -- warning of fatwas issued by the "climate change theocracy," claiming that discussion of climate science has been dominated by "the University of Hollywood and the P.C. …

You’d think people who are willing to blow themselves up any day now wouldn’t worry too hard about the future of the planet. But as it turns out, it really isn’t possible to get MORE cynical about the future than a congressional Republican -- even if you’re an Islamic militant. Last October, Hezbollah guerilla chief Sayyed Hassan Nasrallah told reporters that "the climate threat today is among the biggest threats faced by mankind in (terms of) its peace, security, stability and existence," Reuters reported after Nasrallah attended a tree-planting event in Lebanon. When massive floods inundated Pakistan last year, Osama …

Grist’s offices are in Seattle, so we take this one really seriously: Climate change is threatening Costa Rica’s coffee crops. Coffee’s a fussy little plant, and it can’t handle extreme temperatures, so yields are going way down as temperature inches up. And if you think that’s a buzzkill, try this: An independent study by a Berkeley energy analyst found that growing pot indoors uses the same amount of electricity as running 30 refrigerators. Processed cannabis, the study says, gives off 3,000 times its weight in CO2 emissions. Can that possibly be right? Crap, back to mushrooms, I guess.