Recent rainy weather notwithstanding, California is still reeling from the effects of a long-term drought and mandated water conservation. Many water districts are hiking up rates for water use. In southern California, one water district has come up with a system that rewards conservation and penalizes water waste. The system is a model for other water districts around the state and, increasingly, around the country.

To some, deer are a beautiful symbol of nature. To others, they’re a nuisance and a hazard to public health and the ecosystem. Much of that population growth is in suburbs, where hunting isn’t a big part of the culture. But as Craig LeMoult reports, some Connecticut suburbs are so fed up they’re opening up their parks and woods to hunters.

The star resident of the National Zoo is leaving Washington next week. Four-year-old Tai Shan will board the “FedEx Panda Express” to Chengdu, China. Where will they find a mailer large enough for him?

It was a meteorological mystery: global temperatures hadn’t increased dramatically over the Past decade, even though greenhouse gas levels did. It turns out that a temporary decline in water vapor in the Earth’s upper atmosphere has been holding global warming in check.

As China and the United States promise emissions cuts, coal consumption takes center stage. By Monday, as many as two dozen countries will have listed their emissions targets. Experts say countries need to weigh the costs and benefits of continuing to use a technology that produces the largest amount of greenhouse gases.

Carbon dioxide usually gets most of the blame for global warming, but a dramatic increase in methane gas emissions is worrying scientists. Global warming is causing the world’s wetlands to produce more methane gas — which in turn is causing more global warming.

The Environmental Protection Agency has proposed tightening the standard for smog to protect human health. The result would be cleaner urban air. But because of a quirk of atmospheric chemistry, the pollution control measures could contribute to global warming.

Experts say there are only 350 whooping cranes left in the world. Operation Migration, a nonprofit organization, has been using ultralight aircraft to train the birds to migrate south for the winter. They have succeeded in boosting the species’ numbers in recent years.

Scientists attending the American Meteorological Society meeting in Atlanta say the field has weathered a storm created two months ago when hackers released e-mails from some prominent climate scientists. They say the e-mails revealed bad behavior by a small number of researchers and revealed some weaknesses in the scientific process. But the scientists say the e-mails did nothing to undermine the data showing that climate change is real.

From Britain to Beijing, folks have been shivering their way through a remarkably cold and snowy winter. Meanwhile, in parts of the Arctic, it’s downright balmy — though still below freezing. What’s behind all this unusual weather? It’s the Arctic Oscillation — and it’s gone negative.