by Skeptical Science, SkepticalScience.com
The following post from Skeptical Science is by Dana Nuccitelli and John Abraham. It originally appeared on The Conversation. TreeHugger already wrote about the report mention in this post, but this provides more detailed analysis than previously written.
The International Energy Adency has released unpublished estimates of 2010 global CO2 emissions, and the news is not good.  Between 2003 and 2008, emissions had been rising at a rate faster than the IPCC worst case scenario.  However, the global recession slowed the emissions growth considerably, and in fact they actually declined slightly from 29.4 billion tons (gigatons, or Gt) CO2 in 2008, to 29 Gt in 2009.
However, despite the slow global economic recovery, 2010 saw the largest single year increase in global human CO2 emissions from energy (fossil fuels), growing a whopping 1.6 Gt from 2009, to 30.6 Gt (the previous record annual increase was 1.2 Gt from 2003 to 2004).  As illustrated in Figure 1, in 2009 we had dropped into the middle of the IPCC Special Report on Emissions Scenarios (SRES) scenarios, but the 2010 increase has pushed us back up toward the worst case scenarios once again.
Currently, in terms of both cumulative and annual emissions, we are on track with Scenario A2, the description of which matches what’s happening in the real world fairly accurately thus far:
•    Relatively slow end-use and supply-side energy efficiency improvements (compared to other scenarios).
•    Delayed development of renewable energy.
•    No barriers to the use of nuclear energy.

The major exception being that several countries are transitioning away from nuclear power in the wake of the Japanese Fukushima disaster, which could slow emissions reductions even further.  So, what does continuing on our current path look like?
Scenario A2 puts us at 850 ppm atmospheric CO2 in 2100, with an average global surface temperature 3.5°C hotter than in 2000 (more than 4°C above pre-industrial levels).  If we return back up to Scenario A1FI (fossil fuel intensive), which we were exceeding until the global financial crisis, we’re looking at 950 ppm CO2 and 4°C global warming over the 21st Century (more than 4.5°C above pre-industrial temperatures in 2100).
Clearly this is very bleak news. In an interview with The Guardian,  IEA Chief Economist Fatih Birol said:
I am very worried. This is the worst news on emissions…It is becoming extremely challenging to remain below 2 degrees. The prospect is getting bleaker. That is what the numbers say.

Indeed, limiting global warming to 2°C above pre-industrial temperatures, which is considered the ‘danger limit’ but which may even be too risky, is a challenge to achieve even in the most optimistic IPCC CO2 emissions scenarios.  In fact, the UK Hadley Centre Met Office recently found that just to limit global warming to 3°C, we should have started taking serious action to reduce emissions in 2010 (Figure 4).
(Source: www.treehugger.com )