Scientists are to hold an emergency summit to warn the world's politicians they are being too timid in their response to global warming.

Climate experts from across the world will gather in Copenhagen next month to agree on a stark message to policy makers, which they hope will break the political deadlock on efforts to curb rising temperatures. The meeting follows "disturbing" studies that suggest global warming could strike harder and faster than expected.

It comes ahead of a year of high-level political discussions on climate change, which climax with international negotiations in Copenhagen in December, where officials will try to hammer out a successor to the Kyoto protocol.

Katherine Richardson, a marine biologist at the University of Copenhagen, who is organising next month's event, said: "This is not a regular scientific conference. This is a deliberate attempt to influence policy."

The meeting will publish an update to the 2007 report of the Intergovernmental Panel on Climate Change (IPCC). Richardson said the IPCC report was "wishy-washy" on issues such as sea level rise. "The IPCC talks of a 40cm sea rise this century. Well, if the consensus now is a rise of a metre or more then they need to know that."

A number of studies published since the IPCC report was prepared show that carbon emissions are rising faster than expected and that existing greenhouse gas targets may not be enough to prevent catastrophic temperature rise. Climate experts, including Jim Hansen, of Nasa, have warned about so-called "tipping points" that could lead to runaway warming and rapid sea level rise.

Bob Watson, a former head of the IPCC and chief scientist in the environment department, Defra, said: "Certainly in Defra they're aware of the situation. Whether all governments are aware of it is another matter. Even without the new information there was enough to make most policy makers think that urgent action was absolutely essential. The new information only strengthens that and pushes it even harder."

One issue to be addressed next month is whether it is still possible to limit average global temperature rise to 2C, which the EU defines as dangerous. Richardson said a key question for politicians is the balance between efforts to limit warming and steps to adapt to the likely consequences. Watson has warned that nations should prepare for an average rise of 4C. The IPCC said temperatures could soar by up to 6C by 2100 if current rates of carbon pollution continue.

Martin Parry, a British scientist who jointly chaired the IPCC working group on impacts for the 2007 report, and will attend next month's meeting, said: "I think it's a good idea. I would have thought most of this stuff is out there already but it deserves to be brought together and hammered home in a credible way."

A number of "disturbing" trends seem to have accelerated since the IPCC report was published, he said, such as a decrease in the amount of carbon pollution absorbed in the oceans, and an increase in Greenland ice melt. But he denied that the new findings made the IPCC report obsolete. "They are not so radical as to undermine the report. They reinforce it."