President Barack Obama addresses the Climate Change Summit at the UN General Assembly in New York, New York on Tuesday September 22, 2009.

Chinese President Hu Jintao said in New York on Tuesday that the international community should tackle global climate change through common development, calling for international efforts while pledging China's continued commitment on the issue. He spoke of reducing the “carbon intensity” of his fast-growing economy by cutting emissions as a percentage of future economic output, by a “notable” margin while President Obama told the audience of some 100 heads of state and government that “unease is no excuse for inaction.” The US and China are the world's biggest polluters.

"Global climate change has a profound impact on the existence and development of mankind and is a major challenge facing all countries," Hu said in an address at the UN climate change summit.

"Climate change is an environment issue, but also, and more importantly, a development issue," he said.

The Chinese president outlined four principles needed for a successful concerted effort to deal with climate change worldwide.

Hu said that fulfilling respective responsibilities, achieving mutual benefit and a win-win outcome, promoting common development and ensuring financing and technology were of utmost importance in making these efforts work.

President Obama referred to two categories of developing nations, without naming them. Nations with a strong industrial base - - for example China, India and Brazil - - would have to accept curbing their emissions in any new global agreement . But the poorest nations, he said, deserve financial and other aid to tackle current climate problems and future green development.

In addition to committing to reducing the amount of carbon dioxide it emits to produce each renminbi of gross domestic product by a “notable margin” by 2020 compared with 2005 levels, President Hu said China would increase forests by 40 million hectares (about 98.8 million acres); increase nuclear or nonfossil fuels to 15 percent of power by 2020 and work to develop a green economy.

“Never before has the United Nations brought together Heads of State and Government with leaders of business and civil society at such a scale,” declared UN Secretary-General Ban Ki-moon, who decided after the first private sector Forum on the Millennium Development Goals and Food Sustainability in 2008 to hold an annual forum to ensure that the private sector could contribute to intergovernmental negotiations during the opening of the General Assembly.

Former US Vice-President Gore, founder of the Alliance for Climate Protection, said corporate teams were “way ahead” of governments on climate change, although carbon lobbies in some countries, including the United States, were hampering progress.  Predicting that innovation towards a low-carbon economy could drive the world economy even more than the transition to the Internet had done, he stressed that, in any case, the alternative to concluding an agreement in December at Copenhagen, was unacceptable.

Chinese President Hu Jintao addresses the United Nations Climate Change Summit at the UN headquarters in New York, September 22, 2009.

Danish Prime Minister Rasmussen underscored the importance of true commitment to a solution that supported green growth and sustainable development.  Conceding that fundamental changes were always difficult, he maintained that those who acted now would be the heroes of the future.  Jamshed Irani, Chairman of India’s Tata Group, said that while there must be no recriminations for past “overdraws” of atmospheric resources by industrialised countries, the deal sought at Copenhagen must include the “equitable distribution of nature’s bounties”.

Global greenhouse gas emissions

Global greenhouse gas emissions are on an accelerating trend and if left unchecked, could lead to a 6.4 degree C (11.5 degree F) temperature increase by the end of the century, exceeding conservative estimates, Dr. Rajendra Pachauri, Chair of the Intergovernmental Panel on Climate Change (IPCC) told delegates at the UN last month.

And while he noted that it was good that some governments had adopted a goal of keeping temperature rise to 2°C, most governments had overlooked one important aspect of that goal, and that is to ensure that emissions peak in 2015.

With an average warming of over 2.5°C, Pachauri said “we are going to see some very serious changes.”

Pachauri noted that even though climate change cannot be blamed for any particular storm or disaster, the rising sea level is putting more people at risk. He said a cyclone, such as Nargis which claimed 140,000 lives in Myanmar a year ago, picks up water above the continental shelf, and if that is 17 centimeters higher to begin with, it creates greater devastation.

“The fact is,” Pachauri said, “if you’re living in low lying coastal states, that can be a very serious development.”

The IPCC, in its 2007 Fourth Assessment Report, predicted average global temperature rises of 1.1 – 6.4 degrees C (2 – 11.5 degrees F) by 2100, noting, however, that its best estimate is between 1.8 and 4 degrees C (3.2 – 7.2 degrees F).

The scientific body also underscored that climate change is not a smooth, linear progression but rather a disruption in the climate system, manifesting itself through more floods, droughts and heat waves, whose severity will only increase. “The trend is unmistakably one of far more intense events taking place as a result of climate change”, Pachauri said.

Speaking at an event organized by the Missions of Pakistan and Sweden, Pachauri said that adding even a 1.8 degree C rise to the 0.74 degree C (1.3 degrees F) rise that took place in the 20th century could lead to an average warming of over 2.5 degrees C (4.5 degrees F) in two centuries.

That scenario could create abrupt and irreversible changes, including the possible extinction of 20-30 per cent of all species and collapse of the Greenland and Antarctic ice sheets, which could create sea-level rise of several metres.

"We need to stabilise the atmosphere," he said, and absorb what emissions already exist. He pointed out that greenhouse gas emissions registered a “stupendous” 70 per cent increase between 1970 and 2004.

At the same time, taking action is hardly costly, he said. To stabilise temperature increase to 2 degrees C (3.6 degrees F), the cost would be no more than 3 per cent of global GDP in 2030. “That is clearly not a very high price to pay for avoiding all the negative impacts of climate change.”

Pachauri said all the technologies and methods required to stringently mitigate missions are available. “What is needed is a policy framework that would bring about a movement to low-carbon technology development. Placing a price on carbon would send a direct signal to markets and consumers of a desire to move in that direction.”

Pachauri said that while the message on climate change has been publicised for decades, in the past, these voices had not been heard. Today, he added, people have the benefit of extensive IPCC research and better understanding.