By Richard Black
Environment correspondent, BBC News website
Climate change is "potentially the most serious threat there has ever been" to security and prosperity, according to Britain's new climate ambassador.
Climate change will compromise food supplies, John Ashton believes
In an article for the BBC News website - his first since taking the post in June - John Ashton says climate change must be tackled "whatever it costs".
He argues that the costs of not solving it will inevitably be larger.
Environmentalists welcomed Mr Ashton's appointment, but warned the UK position is undermined by its rising emissions.
Greenhouse gas production is increasing in virtually every country, and it is this that Mr Ashton believes makes climate change a real and urgent threat in Britain and around the globe.
"We need to treat climate change not as a long term threat to our environment, but as an immediate threat to our security and prosperity," he writes.
"We need to see the pursuit of a stable climate as an imperative to be secured whatever it costs through the urgent construction of a low carbon global economy, because the cost of not securing it will be far greater."
Depending on diplomacy
As special representative on climate change for the British foreign secretary, John Ashton's main role is to build a new international consensus on climate change.
Consensus and diplomacy are, he writes, the only ways to tackle climate issues; unlike more traditional security concerns, the "hard power" option of solving a problem by force is not available.
"You cannot use military force to make everyone else on the planet reduce their carbon emissions. No weapon system can halt the advance of a hurricane bearing down on a city, or stem the rising sea, or stop the glaciers melting," he writes.
He believes that climate change, if it is not tackled effectively, will bring conflict through its impacts on societies and economies.
The lawlessness of New Orleans following Hurricane Katrina and the horrors of Darfur, exacerbated by changes to rainfall patterns, "...illustrate how an unstable climate will make it harder to deliver security unless we act more effectively now to neutralise the threat."
According to Felix Dodds, co-editor of the recent book Human Environmental Security - an Agenda for Change, diplomatic failure on climate change may well lead to conflict.
"John Ashton is right in his analysis, and international discussions are critical to solving this issue," he said, "because the alternative is you do end up with military solutions.
"There is a time window, and that window is 10 to 15 years - if we don't deal with it now, the reality is we will have to use military means to secure water, food, and energy security."
John Ashton does not indicate which model of diplomacy he will pursue.
Traditionally, governments negotiated climate agreements through the United Nations, an approach which produced the UN Climate Change Convention and later the Kyoto Protocol.
More recently, Tony Blair spearheaded another initiative, pursuing energy security and climate change simultaneously in talks with G8 member states and a number of developing countries; a third forum, the Asia-Pacific Partnership on Clean Development and Climate, claims to combat climate change through technology alone, even though its own forecasts predict it will fail to reduce greenhouse gas emissions.
Neither of these initiatives involve binding targets and timetables for cutting emissions as the Kyoto treaty does.
While British and European Union officials say they are working towards a post-Kyoto global treaty with targets and timetables, Mr Blair indicated last year that he believes such an outcome is unlikely.
And in its climate change review, launched in March, the government admitted it is likely to fail to meet the target of reducing carbon dioxide emissions by 20% by the year 2010 which it set a decade ago.
Against this mixed backdrop Mr Ashton will need all the diplomatic skills he acquired during his long Foreign Office career if he is to create a new consensus able to bring real emission cuts.
But his commitment to that end is clear in his article.
"If we fail to see this threat to security very soon for what it is and make our dispositions accordingly, we will end up paying far more and experiencing more insecurity," he writes.