The rampant nuclear-power lobby in Britain suffers major setbacks as the full cost of decommissioning old power stations becomes clear (£56 billion and rising at the last count).

The replacement of Britain’s Trident nuclear submarine force becomes an unexpected issue as Tony Blair faces yet another backbench challenge.

The United States department of energy is revealed to be developing new mini-nukes in a programme kept from Congress and funded out of the "black budget". Bush says it is essential to fighting the war on terror but doesn't say how.

The climate of the near-Arctic is shown to be warming up even faster than thought. As the permafrost melts, vegetation frozen for many thousands of years starts to decay. Climatologists say this will release millions of tons of methane, a far worse greenhouse gas than carbon dioxide.

A United Nations Environment Programme (Unep) report says carbon emissions must be halved within ten years and halved again in the following decade if climate change is to be reversed.

Tony Blair has a "road to Damascus" conversion, gives up on nuclear power and announces a massive programme to promote energy conservation and renewables, together with increased tax on petrol and diversion of all proceeds into public transport. He aims to meet the Unep target even if it costs Labour the next election, and challenges David Cameron to back him. Cameron keeps quiet.

Iraqi and Afghan insurgencies continue with no let-up but Bush announces 20,000 troops out of Iraq and 5,000 out of Afghanistan ahead of the Congressional elections in November.

More paramilitary attacks across Europe – London, Rome and Warsaw targeted.

US aircraft carrier sunk in the Persian Gulf by Iraqi pilot flying a 747 freighter loaded with fuel and explosives. 5,000 American sailors killed. Pilot's family had been killed in a US raid on Fallujah in November 2004.

Bush reverses troop cuts, orders reprisal attacks on Fallujah killing 15,000. Insurgency escalates and US casualties soar.

Blair has yet another conversion and announces that the war on terror is failing. Distances himself from Bush and pulls British troops out of Iraq. Sets up a task force of the most independently-minded security experts from Europe, the US and the middle east to propose alternative policies. Backed by Germany, Spain and even France.

Democrats finally mount united opposition to Bush and clean up in the elections. Year ends as families in Iraq, Europe and the United States mourn their losses.