{"id":511,"date":"2008-05-19T11:20:23","date_gmt":"2008-05-19T16:20:23","guid":{"rendered":"http:\/\/blogs.edf.org\/climate411\/2008\/05\/19\/ice_core_record_800ky\/"},"modified":"2008-05-19T11:20:23","modified_gmt":"2008-05-19T16:20:23","slug":"ice_core_record_800ky","status":"publish","type":"post","link":"https:\/\/blogs.edf.org\/climate411\/2008\/05\/19\/ice_core_record_800ky\/","title":{"rendered":"Highest CO2<\/sub> and Methane in 800,000 Years"},"content":{"rendered":"

Lisa MooreThis post is by Lisa Moore, Ph.D.<\/a>, a scientist in the Climate and Air program at Environmental Defense Fund.<\/i><\/p>\n

In IPCC<\/a>‘s Third Assessment Report (2001), scientists reported that carbon dioxide (CO2<\/sub>) and methane levels were higher than at any time in the past 420,000 years. In their latest report (2007), IPCC scientists raised the number to 650,000 years.<\/p>\n

Last week, scientists again revised the number upward. New research shows that CO2<\/sub> and methane levels are higher today than they have been in at least 800,000 years.<\/p>\n

Here’s how they know.<\/p>\n

<\/p>\n

The research, published in Nature<\/a><\/i>, analyzes the atmospheric gases trapped in ice cores extracted from Antarctica. These ice cores are the oldest yet studied. In 2001, the 420,000-year old Vostok ice core from eastern Antarctica set the benchmark. In 2005, scientists analyzed a 650,000-year record from Antarctica’s Dome C. Now, drilling even deeper, scientists at Dome C have assembled an 800,000 year record of CO2<\/sub>, methane and temperature.<\/p>\n

These are the main findings:<\/p>\n