The report, which lays out the effects of global warming on specific US regions and sectors, calls for quick policy action as the US House of Representatives prepares to vote soon on a bill to reduce US greenhouse gas emissions.

'It's not too late to act,' said Jane Lubchenco, the administrator of the National Oceanic and Atmospheric Administration, while releasing the report.

'Human induced climate change is a reality, not only in remote polar regions (and) in small tropical islands, but every place around the country - in our own backyards.'

The House climate bill aims to reduce carbon emissions 17 per cent by 2020 and 83 per cent by 2050. Its success is considered crucial to US legitimacy at international talks on climate change in December, but chances of passage in the US

Senate are unclear. The United States is the biggest per capita emitter of the climate-warming gas carbon dioxide.

Authors of the report said it was not meant to back a specific policy proposal, but they underscored the consequences of failing to reduce carbon dioxide emissions, which are blamed by scientists for contributing to global warming.

In the agriculture sector, for example, the results of climate change would be largely negative.

Increased heat waves and droughts would affect crop and livestock production while more frequent heavy downpours of rain would reduce crop yields.

'Many crops show positive responses to elevated carbon dioxide and low levels of warming, but higher levels of warming often negatively affect growth and yields,' the report said. -- REUTERS