Published: 19 Mar 2009 18:16 CET on www.pointcarbon.com
Avoiding a dangerous global temperature rise depends on where the US sets its mid-term target.
This is the finding of a new report by non-profit research group Climate Analytics, which examined the relationship between the likely US mid-term GHG target and the risk of global temperatures exceeding 2 degrees Celsius.
UN negotiations have followed the scientific findings of the Intergovernmental Panel for Climate Change (IPCC) that 2 degrees Celsius is the highest acceptable increase in temperature to avoid irresistible climate change.
The IPCC in its latest report concluded that rich countries need to slash their emissions by 25-40 per cent below 1990 levels by 2020 to avoid runaway climate change.
But the new lead climate change negotiator for the US, Todd Stern, said this month it is neither necessary nor possible for the US to achieve those mid-term cuts, and that reductions can be deferred and achieved by 2050.
“A delay in achieving emission reductions consistent with the 25-40 per cent annex I (rich country) reductions would likely lead to delay by others,” according to the report.
“It is in this context that the administration of President Obama faces difficult dilemmas.”
The report says that the lack of climate change action undertaken by the preceding Bush administration means the US was 16 per cent above 1990 levels in 2006, making it too difficult for it to heed IPCC recommendations.
The Obama administration has said it intends to get Congress to pass legislation mandating that domestic emissions return to 1990 levels by 2020 and 80 per cent below that by mid century.
If global emissions return to 1990 levels in 2020, “the chance that 2 degree celsius warming is exceeded is estimated as roughly one in six, which rises to one in four if global emissions are still 40 per cent above 1990 in 2020,” the report finds.
Deferring the 2020 emission reductions by 10 years, as Todd Stern has suggested, would result in much higher cumulative GHG emissions and increases the rate of emissions reductions in the future, the report said.
The probability of exceeding 2 degree Celsius warming is increased by about 15 per cent for such a delay, increasing the risk that reductions can not be compensated for by steeper reductions in later years.
A delay in emission reductions from 2020 to 2030 also causes a higher overall emissions level in 2020, converting an “emission pathway with about a one in seven chance of exceeding 2 degrees to a one in four chance,” according to the report.
By Valerie Volcovici –