"How much money is enough to fight climate change?" "Who should provide the money?" These were questions thrown at the UN climate change chief by journalists at a pre-summit press conference in Copenhagen.

Funding for adaptation to climate change has been one of the core issues on the negotiation table and has indeed attracted much attention in the past several years.

Yvo de Boer said at least 10 billion U.S. dollars is needed each year in the next three years to help developing countries address the challenge. Hundreds of billions of dollars should be in position to fight the global issue in the long run, he said.

In his reply to the who-should-pay question, de Boer mentioned the names of the European Union (EU), the United States and Japan.

As a matter of fact, the UN Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol have provided an unequivocal answer: developed countries should pay. The reason is simple: today's global warming is to a large extent of their making.

According to statistics, developed nations emitted 95 percent of the carbon dioxide (CO2) from fossil fuels from the beginning of the Industrial Revolution in the 18th century till 1950.

From 1950 to 2000, developed countries were responsible for 77 percent of total global CO2 emissions.

Even today, developed countries are consuming more than 70 percent of the world's energy with less than one fifth of the world's total population and discharging over half of the greenhouse gases. Per capita emissions in the majority of developed countries are way higher than world average.

Meanwhile, developing countries are victims of the deteriorating environment, and some islands countries are even facing a risk of being submerged.

As a result of moral pressure, some developed nations have claimed that they are willing to provide funding to help developing countries cope with the impact of climate change. But so far no concrete commitments have been made.

Certain developed countries even attempted to make developing countries pay, in one way or another, for climate change, totally ignoring the principle of "common but differentiated responsibility" under the Kyoto Protocol.

The Association of Southeast Asian Nations issued a statement on the eve of the Copenhagen conference to reaffirm its justified demand for development. The bloc urged developed nations to provide financial support for the fight against climate change.

If the world is a big family, and some family members got rich at the expense of others, should they pay to return the family to good order?