greenhouse gases

EDITOR'S NOTE 11/18/13: After this blog post was published, the IPCC updated its Summary for Policymakers. The figures in this blog post have been updated to reflect new information.

The Intergovernmental Panel on Climate Change’s (IPCC) Fifth Assessment Report (AR5) has delivered an overwhelming consensus that climate change impacts are accelerating, fueled by human-caused emissions. We may have just about 30 years left until the world’s carbon budget is spent if we want a likely chance of limiting warming to 2 degrees C. Breaching this limit would put the world at increased risk of forest fires, coral bleaching, higher sea level rise, and other dangerous impacts.

When Will Our Carbon Budget Run Out?

The international community has adopted a goal for global warming not to rise above 2°C compared to pre-industrial temperatures. Scientists have devoted considerable effort to understanding what magnitude of emissions reductions are necessary to limit warming to this level, as the world faces increasingly dangerous climate change impacts with every degree of warming (see Box 1).

IPCC AR5 summarizes the scientific literature and estimates that cumulative carbon dioxide emissions related to human activities need to be limited to 1 trillion tonnes C (1000 PgC) since the beginning of the industrial revolution if we are to have a likely chance of limiting warming to 2°C. This is “our carbon budget” – the same concept as a checking account. When we’ve spent it all, there’s no more money (and the planet’s overdraft fees will be much more significant than a bank’s small charges for bounced checks).[^1]

Low-carbon development has become the core theme of China’s urbanization. In fact, it’s one of the country’s key strategies to achieve its target of reducing carbon intensity by 40-45 percent by 2020.

China’s National Development and Reform Commission (NDRC) has identified 36 pilot cities and assigned them several tasks.

Natural gas wells represent a significant source of U.S. greenhouse gas (GHG) emissions, as many of them leak methane, which is more than 20 times more potent than carbon dioxide. But while scientists know that “fugitive methane” is a concern, there’s much uncertainty about the full extent of the problem. A new study from the University of Texas—developed in partnership with the Environmental Defense Fund and nine natural gas production companies (Anadarko, BG Group, Chevron, EnCana, Pioneer, Shell, Southwest, Talisman, ExxonMobil)—sheds some light on this perplexing issue.

International climate action took an encouraging step forward today. President Obama reached agreements with the G-20 and with China to phase down the use of hydrofluorocarbons (HFCs), potent greenhouse gases used in appliances like refrigerators and air conditioners.

As extreme weather events like wildfires, heat waves, downpours, and droughts continue to make headlines in the United States and around the world, many have wondered what their connection is to climate change. A new report sheds some light, firmly drawing correlations between several extreme weather events in 2012 and human-induced warming.