As world leaders converge in New York City Tuesday for an United Nations Climate Summit, some developed countries are being confronted with the same-old question, when are you going to act?

In a seemingly well-intentioned gesture, US President Barack Obama is expected to announce new US help for other nations to combat global warming, in addition to touting its own progress in this regard.

However, analysts say Uncle Sam is just eager to leverage its own efforts and commitments to pressure China and galvanize support for a game-changing deal in the global fight against climate change.

It is hardly just a coincidence that many Western media have recently rushed to drag China into the limelight by hyping up its status as the world's largest greenhouse gas emitter which they say should shoulder a major bulk of responsibilities in emission reduction.

In the global climate fight, the international community has long upheld the principle of "common but differentiated responsibility" under the 1997 Kyoto Protocol -- the only legally binding emission-reduction agreement ratified by nearly 200 countries.

However, some developed countries, ignorant of both historical facts and present reality, want to see the cornerstone principle scrapped in a new global treaty so that their "burdens" could be lessened.

As a matter of fact, their actions have already been much delayed. Research data has suggested that developing nations have accounted for 70 percent of all the greenhouse gas emissions cuts in the world.

The irresponsible attitude of some developed countries is a major reason why years of efforts by the international community to push forward the global fight against climate change have been caught in a deadlock.

There are good reasons why the developed countries should give their best efforts to act against global warming.

Just like saying that "Rome is not built in one day," the climate peril we are facing right now is not just an outcome of the industrial growth of developing countries, most of which only started several decades ago. Instead, it has been constantly building up since the onset of the industrialization -- a process that has lasted for over two centuries.

Meanwhile, with a rapid process of globalization, developed countries are shifting their high energy consuming and polluting industries to the developing world, thus transferring more carbon emissions to the latter.

In the case of China, the world's most populous nation is facing the daunting task of modernizing its economy for the benefit of a whopping 1.35 billion population -- nearly one fifth of the world's total, while it remains troubled by a barrage of growing woes such as development imbalance and poverty alleviation.

Therefore, it is extremely unreasonable and selfish for those developed countries, which have emitted their historical share of heat-trapping gases and are relocating their current share, to pass the buck to developing nations and infringe their very right of development.

Meanwhile, as a responsible developing country, China, though not facing binding targets under the existing Kyoto Protocol, has made self-motivated efforts in emission reduction.

To show its determination, China has recently pledged to nearly halve its carbon emission intensity, namely emissions per unit of the GDP, from the 2005 level by 2020.

It is noteworthy that despite being termed as the world's "top polluter," China's per-capita emissions of greenhouse gases are far lower than those of developed countries, especially the United States.

The new global treaty, set to be finalized next year in Paris, should be a manifestation of the common will and determination of the human race to correct their wrongdoings and fight for a better future, instead of a freak show of their selfishness and petty desires.

It is highly advisable for those developed countries to stop calculating and pointing fingers, and start assuming their due and unshirkable responsibilities.

They might also need to be reminded that the more their actions are delayed, the more difficult and costly they will be in the future.