A man lies on a globe which is a part of an installation in downtown Copenhagen December 6, 2009. Copenhagen is the host city for the United Nations Climate Change Conference 2009, from December 7 until December 18.[Xinhua/Reuters]

The world is arriving in Copenhagen with unprecedented unity in order to seek a climate pact, although the historic UN Climate Change Conference has been overshadowed by hacked e-mails and protests around Europe.

At a news conference in the Bella Center, UNFCCC Executive Secretary Yvo de Boer called on the 192 nations represented at the UN climate summit starting Monday "to deliver a strong and long-term response to the challenge of climate change."

Still, De Boer worried that e-mails pilfered would fuel skepticism among those who believe that scientists exaggerate global warming, but defended the research – reviewed by some 2,500 scientists – that shows man has fueled global warming by burning fossil fuels, according to the AP.

E-mails stolen from the climate unit at the University of East Anglia appeared to show some of world's leading scientists discussing ways to shield data from public scrutiny and suppress others' work.

Activists in Europe protested over the weekend to crank up the pressure on world leaders for a strong climate deal ahead of the 12-day UN climate conference.

Thousands of people dressed in blue marched through central London on Saturday, and more than 100 environmental campaigners camped out overnight in London's famous Trafalgar Square.

Similar protests were staged in Berlin, Paris, Brussels and Dublin.

However, this reporter had found Copenhagen enveloped in a pro-climate-deal atmo-sphere up to Sunday afternoon.

Governments and activists welcomed the US' increasing ambition in the conference since US President Barack Obama on Friday rescheduled his original plan to join other world leaders at the crunch December 18 finale.

Indian Prime Minister Manmohan Singh announced he would attend the closing summit in Copenhagen, joining 104 other leaders, including Obama, in a sign of growing momentum for a deal.

"The absence of the US from the Kyoto framework was a serious barrier to effective action to reducing greenhouse-gas emissions globally. This is now changing. We are in a new era," Alex Wang, senior attorney and director of the China Environmental Law project of the Natural Resources Defense Council, told the Global Times Sunday.

According to de Boer, developed countries will need to provide fast-track funding to the order of at least $10 billion a year through 2012 to enable developing countries to immediately plan and launch low-emission growth and adaptation strategies and to build internal capacity.

At the same time, developed countries will need to indicate how they intend to raise predictable and sustainable long-term financing and what their longer-term commitments will be.

Too little time and too little agreement, however, especially between rich and poor countries, mean the 192-nation Copenhagen conference is likely to produce, at best, a framework – a basis for continuing talks and signing internationally binding final agreements next year, said the AP.