The world is careering towards three degrees Celsius (5.4 degrees Fahrenheit) of warming by 2100 despite headline-making promises to curb carbon emissions, a study released at UN talks here said on Thursday.
"The current pledges and loopholes give us a virtual certainty of exceeding 1.5 C (2.7 F), with global warming very likely exceeding 2 C (3.6 F) and a more than 50-percent chance of exceeding 3 C (5.4 F) by 2100," said Bill Hare of Germany's Potsdam Institute for Climate Impact Research (PIK).
Around 120 countries have signed up to voluntary action on greenhouse gases under last December's Copenhagen Accord, which aims to limit warming since pre-industrial times to 2.0 C.
Scientists caution there is no consensus on what is a safe level for warming, and some say a rise of even 2.0 C could still have far-reaching risks for ice and snow cover and rainfall patterns.
The new study takes a fresh look at the promises, pronouncements, policy changes and other measures unveiled, sometimes with fanfare, since Copenhagen.
It rated the contribution by China - the world's No. 1 carbon polluter - as "inadequate" but praised the country for boosting renewable energy.
A voracious burner of fossil fuels, China saw its carbon emissions double from four to eight billion tonnes annually from 1990 to 2005.
On a business-as-usual basis, its output would reach between 12 and 14 billion tonnes by 2020, according to the new Climate Action Tracker analysis. But, if all China's policies are implemented, emissions could remain under 10 billion tonnes per year, it estimated.
Among industrialised countries, the report warned the United States, the No. 2 polluter, would still fall short even if it fulfilled its Copenhagen promises.
Only Norway and Japan are currently in the tracker's "sufficient" category among industrialised countries. However, the European Union (EU) and Iceland could join them by deepening planned emissions cuts from 20 percent by 2020 over 1990 levels to 30 percent.
The analysis was written by experts with PIK, a German energy research company called Ecofys and Climate Analytics, a not-for-profit company which tracks policy commitments in climate change.
It was published on the penultimate day of a 12-day round of talks in Bonn under the UN Framework Convention on Climate Change (UNFCCC), which seeks to shepherd 194 countries towards a post-2012 worldwide treaty.
Reducing emissions has become a fiercely-contested issue because of the cost of easing use of oil, gas and coal, the cheap and abundant fossil fuels that meet most of the world's energy needs.
Temperatures have already risen by around 0.8 C (1.4 F) since the start of the Industrial Revolution, causing worrying glacier melt, snow loss and retreating permafrost and an accelerating rise in ocean levels, according to the UN's Intergovernmental Panel on Climate Change (IPCC).
In addition, 0.6 C (1.1 F) has to be factored in from past emissions that have yet to have an effect because of the inertia of the climate system. As a result, relatively little room is left for further emissions.Reuse content