The National Oceanic and Atmospheric Administration (NOAA) announced last week that carbon dioxide concentrations at the Mauna Loa Observatory in Hawaii surpassed the milestone 400 parts per million for a sustained period.

The Sierra Club is joining and expanding this successful effort to convince even more companies to get on board and go even further to reduce their oil consumption altogether. To date, the climate movement has largely given large corporate oil consumers a free pass. Those days are over.

Sure, disaster porn is always good for ratings, but though a Superstorm Sandy may momentarily raise the specter of climate change, daily bulletins on the parts per million of carbon dioxide in the atmosphere apparently aren't Nielsen enough.

By 2050, California & Southwest Could Have 100% Dry Years NASA Says, reports Climate Progress, according to a NASA analysis, which basically lays out ...

If infrastructure, such as the Keystone XL pipeline, is built to transport tar sands, ways will be developed to extract more and more. When full accounting is done of emissions from tar sands oil, its use is equivalent to burning coal to power your automobile.

International aviation is on course for a rough landing in our warming world. Air travel is growing rapidly -- and so are aviation emissions, which are already responsible for 5 percent of the warming effect of global greenhouse gas emissions.

US Gets Weather Whiplash With Climate Change notes Andrew Freedman at Climate Central. Warming air and oceans mean more moisture in the air, and the ...

Let's say that by some miracle the pause button has been hit on global warming and we have a new window to save the planet. Under such a scenario, what kind of climate piggy would you be?

Carbon dioxide levels in excess of 400 parts per million have already been recorded at the Mauna Loa Observatory in Hawaii, but they tend to fluctuate hourly. The milestone is significant because it illustrates how dramatically humans have altered the atmosphere in a few generations, says Mother Nature Network.

Every serious nation except the U.S. has an energy policy -- we need one. Obama's economic advisers appear not to want to even discuss the idea.

Solar Grew 5x Faster Than Rest of US Economy in 2012, reports Joe Romm at Climate Progress, adding 14,000 new jobs in California, Arizona, New Jersey ...

Every Earth Day, some of us are tempted to say things like "We live on the same planet; we're all in this together." But no, we're not.

Fossil Fuels Investments A $6 Trillion Mistake, if the world addresses climate change, says a London School of Economics study, reports Sally Bakewell...

New York City is not going to wait around for the U.S. Congress to do something rational. Congress is too busy having tea parties, defeating modest gun regulation, and sequestering critical research funds to be considered a serious participant in climate policy.

Carbon logic dictates that if President Obama is at all serious about addressing climate change, he must help put an end to Canada's tar sands folly, ...

The Renewable Energy Kids - Solar, Wind, Geo and Wave (wave to the folks, honey!) - are all growing up at different rates, having been nurtured in ve...

The drive to clean up the world's energy system has stalled: While energy is becoming less carbon-intensive in some sectors and regions, the story of ...

Invest In Clean Energy To Reap Enormous Health Benefits says the UN, reports Alister Doyle at Reuters News, and help slow climate change. Fossil fuel ...

It's Melting, Melting: 1600 Years Worth of Andean Ice Melted in 25, says a new study, reports Justin Gillis at the New York Times. Researchers studyin...

China's Choice: Cut Coal Or Dry Up says a new report highlighting how coal mining and combustion technologies there are drinking up scarcer water supp...

Humanity's Faustian climate bargain is well known. Humans have been pumping both greenhouse gases (mainly CO2) and aerosols (fine particles) into the atmosphere for more than a century. Is the new data we present here good news or bad news, and how does it alter the "Faustian bargain"?

The endless tug of war confuses the common man, who has worries more immediate than climate change. He would like to know, once and for all, if global warming is deadly. To wit, are we are done for, or are some people just blowing hot air?