Gordon Brown's climate change laws will not do enough to prevent " catastrophic" environmental damage and a reversal in human development, a new UN report has claimed.

Released yesterday, the Human Development Report found that developed countries such as Britain would need to cut their carbon dioxide emissions by at least 80 per cent before 2050 to prevent severe and irreversible global damage.

Brown's Climate Change Bill announced earlier this month commits to reducing carbon emissions by just 60 per cent before 2050.

The UN said this target was not only too low, but it did not include pollution generated by shipping and aviation – equating to around 27 per cent of the country's greenhouse gas output.

"Emissions targets in the Climate Bill are not consistent with the objective of avoiding dangerous climate change," the report said.

Earlier this year, Gordon Brown promised that he would respond to concerns about the environmental effectiveness of the government's emission targets, pledging that one of the first acts of the independent climate change committee will be to assess whether the targets should be tightened and whether aviation and shipping should be included.

The report added that measures such as carbon taxes, cap and trade schemes, tighter regulations governing polluters and charges for drivers of gas-guzzling cars would have to be introduced if Britain was to become serious about climate change.

It should also invest significantly more money into forms of renewable energy such as solar, wind, tidal and biofuel power, the report advised.

The message was equally bleak for the governments of other developed nations, with the UN claiming global warming would present a "massive threat to human development" and prosperity if left unchecked.

The poorest countries – including large parts of Africa – would be hardest hit despite the fact they have contributed the least to global warming.

UN development program administrator Kemal Dervis said: "Ultimately, climate change is a threat to humanity as a whole. But it is the poor, a constituency with no responsibility for the ecological debt we are running up, who face the immediate and most severe human costs."

The 400-page paper claimed that by the end of the century entire countries could sink under water, global temperatures could rise by six degrees centigrade and there could be "apocalyptic consequences" for millions of people in developing nations.

The findings of the report are likely to be discussed at next month's UN climate summit in Bali, where negotiators will also draw up plans for a post-2012 Kyoto Protocol.