2050 climate conditions crucial to harmful impacts in 2100

Washington, Jan 13 (ANI): While countries try to come up with new strategies for reducing greenhouse gas emissions, an international team of researchers suggests that policymakers should focus on what needs to be achieved in the next 40 years in order to keep long-term options viable for avoiding dangerous levels.

"Setting mid-century targets can help preserve long-term policy options while managing the risks and costs that come with long-term goals," said co-lead author Brian O'Neill, a scientist at the National Centre for Atmospheric Research (NCAR).

The researchers studied the computer-simulated interactions between the energy sector and the climate system and determined on how emissions levels in 2050 would affect the feasibility of meeting end-of-century temperature targets of either 2 or 3 degrees Celsius above the pre-industrial average.

They began with "business as usual" scenarios, developed for the Intergovernmental Panel on Climate Change's 2000 report, that project future greenhouse gas emissions in the absence of climate policy.

One "business as usual" scenario showed that global emissions would need to be reduced by about 20 percent below 2000 levels by mid-century to preserve the option of hitting the target.

In a second case, in which demand for energy and land grow more rapidly, the reductions by 2050 would need to be much steeper: 50 percent.

However, achieving such reductions is barely feasible with known energy sources.

"Our simulations show that in some cases, even if we do everything possible to reduce emissions between now and 2050, we'd only have even odds of hitting the 2 degree target-and then only if we also did everything possible over the second half of the century too," said co-author and IIASA scientist Keywan Riahi.

The research shows that average global temperatures have warmed by close to 1 degree C since the pre-industrial era.

Much of the warming is due to increased emissions of greenhouse gases, predominantly carbon dioxide, due to human activities. Many governments have advocated limiting global temperature to no more than 1 additional degree Celsius in order to avoid more serious effects of climate change.

"Our research suggests that, provided we adopt an effective long-term strategy, our emissions can be higher in 2050 than some proposals have advocated while still holding to 2 degrees Celsius in the long run," O'Neill added.

The study is published in the Proceedings of the National Academy of Sciences. (ANI)