The pledged cuts to carbon dioxide (CO₂) and other greenhouse gases (GHGs) won’t be enough to hit the targeted 450 ppm of CO₂ thought to be necessary to keep the Earth’s mean temperature from rising more than 2 °C. This isn’t news to anyone who’s followed climate closely for a few months. What’s news, however, is that the UN knew this as well and yet they’re still saying that 2 °C is possible. Earlier today an early draft of an internal UN analysis of GHG cuts leaked, and the document shows that the UN Secretariat knew in advance of the Copenhagen meeting that the cuts wouldn’t be enough.

According to the 2009WEO [World Energy Outlook], global emissions in 2020 are projected to be about 5 Gt for the reference scenario. According to the 450 ppm scenario, global emissions peak around 2015 at the level of 43.7 Gt and remain broadly stable at that level before starting to decline in 2020.

The UN Secretariat’s “reference scenario” puts the global emissions peak at or above 550 ppm, occurring after 2020, and at least 3 °C.

Most scientists studying climate believe that 2 °C is relatively safe for avoiding abrupt climate transitions, but that the higher you go above that, the more likely things are to get really bad really fast.

According to The Guardian:

The analysis seriously undermines the statements by governments that they are aiming to limit emissions to a level ensuring no more than a 2C temperature rise over the next century, and indicates that the last 24 hours of negotiations will be extremely challenging.

Other voice on this news:

• The official COP15 news site quotes Greenpeace:
  

  “The UN is admitting in private that the pledges made by world leaders would lead to a three degree rise in temperatures. The science shows that it could lead to the collapse of the Amazon rainforest, crippling water shortages across South America and Australia and the near-extinction of tropical coral reefs, and that’s just the start of it,” Greenpeace campaigner Joss Garman tells the newspaper.

• 350.org, a group advocating for emissions cuts to 350 ppm, not 450 ppm, says
  

  So if someone–Barack Obama, for instance–tells you that this agreement will hold temperature increases below 2 degrees (itself an unsafe level), just show him this document.

• A. Siegel at Get Energy Smart Now! claims that the “leaked UN documents show that current proposals would lead to a CO2 concentration of 770 ppm by 2100.” This analysis is from Climate Interactive’s Climate Scorecard.
• Democracy Now! has an interview with the journalist who received the leaked document.
• Andy Revkin at the NYTimes blog DotEarth said that “United Nations officials confirmed the document’s authenticity but declined to discuss it.” In addition, he points out that
  

  [3 °C] is far above the thresholds for dangerous warming being debated at the meeting and accepted in recent statements by the major economies of the world.

I’ll update this story as more information is available.