Increasing pressure caused by climate change on essential resources like water could not only trigger domestic conflicts but also have a destabilising effect globally, warn UN officials.

"It is not far-fetched to begin to see growing tensions; not far fetched to think climate change will globally have a destabilising effect," said Achim Steiner, Executive Secretary of the UN Environment Programme (UNEP), who drew a scenario in which countries heavily affected by climate change would blame those not seen as doing enough to cut emissions.

Steiner's comments followed the release of a report, Climate Change as a Security Risk, by the German government's scientific advisory body on 10 December at the UN climate change conference in Bali, Indonesia: it warned that environmental shocks could outpace the adaptive capacities of some societies in the coming decades.

The Intergovernmental Panel on Climate Change (IPCC) has warned that by 2020 up to 250 million people in Africa could be exposed to increased water stress, and food production could be halved. Fresh water availability in Asia was also expected to fall.

"This could result in destabilisation and violence, jeopardising national and international security to a new degree," the German Advisory Council's report commented.

Research in recent decades has shown that land degradation, water shortages and resource competition, when combined with other conflict-amplifying factors, have caused violence and conflict in the past, said the German study. Earlier this year, UNEP cited the war in Darfur as an example of the impact of climate change on stability.

"We are not trying to depoliticise the conflict," said Steiner, "[but] we need to learn, to understand, that if we had taken into account some of the factors [related to climate change], we could have avoided some of the conflicts that have exploded."

Regional hotspots

The German government's report draws scenarios of the social impact of climate change in regional hotspots. Some of them are:

• North Africa: The populous Nile Delta will be at risk from sea-level rise and salinisation in agricultural areas. A drop in food production, water scarcity, high population growth and poor political problem-solving capacity could intensify political crisis and migratory pressure.

• Sahel zone: Drought, water scarcity and food insecurity in a region already characterised by weak states and instability could aggravate social crises.

• Southern Africa: Droughts and water scarcity could overstretch capacities in some of the poorest countries in the world.

• Central Asia: Above-average warming and glacial retreat could exacerbate problems in the region, characterised by political and social tensions.

• India, Pakistan, Bangladesh: Glacial retreat in the Himalayas would jeopardise water supply to millions of people, with sea-level rise and cyclones aggravating crises characterised by cross-border conflicts (India and Pakistan) and unstable governments.

"If we look at South Asia alone, the melting [glaciers would mean] tens of millions of people will have to leave their livelihoods. Where will they go? How will they impact on the host communities that receive them?" said Steiner. "We must look at the potential security threat posed by these changes - we cannot bury our heads in the sand."

Global tensions playing out

The German Council pointed out that rising new powers like China and India, which are set to become the world's biggest emitters of greenhouse gases, and the US's "simultaneous loss of power" could make it difficult to achieve breakthroughs in multilateral climate policy.

It called on the European Union (EU) to play a leading role in convincing the US and Asian powers to come to the party in Bali to help put in place a new deal after 2012, when the first phase of the Kyoto Protocol expires.

The Protocol is a commitment made in 1997 by 36 industrialised countries to reduce greenhouse gas emissions by at least five percent against a 1990 baseline, and forms part of the UN Framework Convention on Climate Change (UNFCCC).

This is an international environmental treaty produced at the Conference on Environment and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro in 1992. The treaty is aimed at reducing emissions of greenhouse gases to combat global warming.

The UNFCCC set no mandatory limits on greenhouse gas emissions for individual nations and contained no enforcement provisions, and so is considered legally non-binding. The treaty included provisions for updates, called "protocols", that would set mandatory emission limits. The principal update is the Kyoto Protocol.

The US has refused to ratify the Kyoto Protocol because it excluded China and India, two of the world's fastest growing economies. At a press briefing on 10 December, Harland Watson, the US Senior Climate Negotiator, reiterated his country's position. He said the US was seeking a "shared global role" in emission reductions.

Watson also indicated that the US had objected to a reference to emission cuts of 25 to 40 percent by 2020 in a draft text of the new deal, as it did not want to predict the outcome of the final agreement expected to be hammered out in 2009, when the next meeting of all parties to the UNFCCC takes place in Copenhagen, Denmark.

Canada and Japan have also objected to the reference to 25 to 40 percent emission cuts in the draft, "but they are not backing the US position, they want the US to make a commitment before they do," explained Martinus van Schalkwyk, South Africa's environment minister.

Steiner said a new climate agreement should reflect the findings of the scientific community, which has called for a 25 to 40 percent cut by 2020 to avoid a 2-degree Celsius increase in global temperature.

That kind of temperature rise is expected to destroy 30 to 40 percent of all known species, with bigger, fiercer and more frequent heat waves, floods and droughts.