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"Two things are happening," said study co-author William D'Andrea, a paleoclimatologist at Columbia University's Lamont-Doherty Earth Observatory. "One is you have a very gradual decrease in the amount of sunlight hitting high latitudes in the summer. If that were the only thing happening, we would expect these glaciers to very slowly be creeping forward, forward, forward. But then we come along and start burning fossil fuels and adding carbon dioxide to the atmosphere, and glaciers that would still be growing start to melt back because summer temperatures are warmer."

Glaciers are dynamic and heavy. As a glacier moves, it grinds the bedrock beneath, creating silt that the glacier's meltwater washes into the lake below. The larger the glacier, the more bedrock it grinds away. Scientists can take sediment cores from the bottom of glacier-fed lakes to see how much silt and organic material settled over time, along with other indicators of a changing climate. They can then use radiocarbon dating to determine when more or less silt was deposited.

Government ministers arrive in Paris today as climate talks enter their second week. The ministers add high-level influence to the climate negotiations and can help unlock critical elements of a new climate deal.

“It’s going to be quite a sprint for ministers to secure a strong deal by Friday,” said Tasneem Essop, head of WWF’s delegation to the COP21 climate talks. “The French presidency now has the responsibility to take us to the finish line.”

As representatives from more than 190 countries convene in France for the second week to address ways to slow global warming, an MIT-led team has published a paper outlining a set of options for incorporating equity considerations in a national Emissions Trading System (ETS) for China that could reduce carbon emissions while minimizing economic impact on poorer or less-developed regions.

The paper, “Equity and Emission Trading in China,” published in the journal Climatic Change, outlines a sophisticated menu aimed at Chinese policymakers showing how the burden of reducing carbon emissions could be shared or divided across the country’s provinces under a market-based carbon pricing system.

“Emission trading systems have been shown to be highly effective when they are allowed to work, but one of the toughest challenges involves how to distribute the cost,” said lead author Valerie Karplus, Assistant Professor of Global Economics and Management at the MIT Sloan School of Management. “We compare alternative schemes for allocating emissions rights that can effectively de-couple who pays for reductions from where the reductions actually occur.”

The rainfall and snowpack so far this autumn have been encouraging, but the stubborn reality is that California is still mired in drought. While farmers from Bakersfield to Fresno to Redding are screaming about water quotas, California residents say they are doing what they can, from pulling out grass lawns to capturing what little rainwater exists.

Es difícil no pensar en un cactus como planta resistente. Viven en climas calientes afectadas por la sequía, y si pueden sobrevivir allí, seguro que pueden hacerlo en cualquier parte. Tristemente, este supuesto no es la realidad de los cactus. Como un equipo internacional de investigadores descubrió, casi un tercio de todas las especies de cactus se enfrentan a una amenaza inminente de extinción.