The leaders of the eight most industrialized countries have taken a positive step toward tackling climate change during their summit meeting in L'Aquila, Italy, by vowing to limit global warming to within 2 degrees celsius above pre-industrial levels.

It is the first time that the G8 leaders have accepted such a political goal in the global fight against climate change. The joint commitment is of vital importance for the future of this planet as the global climate is expected to become warmer by a few degrees within just a few decades if no remedial measures are taken now.

The dangerous effect of this seemingly small-scale rise in temperature should not be underestimated. It was a warming of the global climate by just a few degrees - though over the course of thousands of years - that had brought an end to the last ice age. Scientists have warned that there would be serious climate consequences if the world temperature rise exceeds the threshold of 2 degrees celsius. What the world leaders agree on today will have a far-reaching effect over whether a global disaster can be averted in the decades to come.

Thus, it is regrettable that the leaders remain vague about specific targets for their own countries, which cannot but cast doubts over their determination and earnestness in addressing the urgent issue. Without setting a good example, they will find it hard to make common cause with the emerging economies in this fight against a peril that threatens all mankind.

Meanwhile, it is noticeable that the G8 countries, out of consideration of their own interest, have watered down the target of halving greenhouse gas emissions by 2050. While pledging to cut global emissions of greenhouse gases by at least 50 percent by 2050, they didn't specify the baseline year.

The EU has been in favor of the base year of 1990, while the US wants to use as the reference the level of 2005, which is much higher than that of 1990. Leaving the issue open means there would be a bigger tug-of-war over how and what concessions could be made in the run up to the UN Climate Change Conference to be held in Copenhagen later this year.

The leaders of the five emerging economies, known as G5, are justified in reaffirming the principles of common but differentiated responsibilities and respective capabilities.

The developing nations - being the most vulnerable to the adverse effects of climate change - are in dire need of help from the developed world to adapt to the challenges of global warming.

The developed countries - which are responsible for generating 90 percent of the greenhouse gases in the past half century - must shoulder the responsibility to provide climate-friendly technology, financing and capacity building to support and enable developing countries to take "mitigation actions in the context of sustainable development". This is a responsibility that the developed countries can shirk only at their own peril.

(China Daily 07/10/2009 page8)