On November 5, 2001, the United Nations declared November 6 of each year as the International Day for Preventing the Exploitation of the Environment in War and Armed Conflict.

History has been witness to many deliberate acts to destroy or exploit the natural environment to achieve military goals. In the 5th century BC the retreating Scythians poisoned the water wells in an effort to slow the advancing Persian army. Roman troops razed the city of Carthage in 146 BC and poisoned the surrounding soil with salt to prevent its future cultivation. The American Civil War saw the widespread implementation of ''scorched earth'' policies.

In August 1945 the United States detonated atomic bombs over Hiroshima and Nagasaki, resulting in massive loss of life and environmental destruction. During the Vietnam War, the US implemented Operation Ranch Hand, to devastating effect, to destroy vegetation used by its enemy for cover and sustenance, using chemicals such as Agent Orange.

More recently still, who can forget the haunting images of more than 700 burning Kuwaiti oil well-heads which had been deliberately ignited by retreating Iraqi forces during the Gulf War in 1991 a scene that was likened to Dante's Inferno. Over the following 10 years the Saddam regime built barriers and levees to drain the al-Hawizeh and al-Hammar marshes in southern Iraq, an area some believe is the site of the biblical Garden of Eden. This effectively destroyed the livelihood of the 500,000 Marsh Arabs who had inhabited this unique ecosystem.

Acts of significant and deliberate environmental destruction, exploitation and contamination during armed conflict have continued in more recent times, including the use of cluster bombs and weapons containing depleted uranium by US and British forces in Iraq.

At this moment the world is witnessing a continuing humanitarian and environmental catastrophe in the western region of Darfur in Sudan, which has seen the poisoning of water wells and drinking water installations as part of a deliberate government-supported strategy by the Janjaweed militia to eliminate or displace the ethnic black Africans living in that region.

Actions such as these demonstrate how the deliberate despoliation of the environment can have catastrophic effects, not only on human populations, but also in ecological terms. For example, nuclear, biological and chemical weapons, as well as having the potential to kill many thousands of people in a single attack, have effects that may persist in the environment, in some cases indefinitely. The devastating effects of environmental warfare can continue long after the conflict is resolved, jeopardising or destroying the lives and livelihoods of those reliant on the natural environment and increasing numbers of refugees. There are currently 37.4 million refugees from conflicts, according to a 2008 report by the UN High Commissioner for Refugees, an increase of about three million over the previous year.

Moreover, access to natural resources or the lack of access can itself be the trigger for conflict. In both the Democratic Republic of Congo and Haiti, the United Nations Environment Program has reported that environmental damage has been a major cause of conflict. Some five million people were killed during the 1990s in armed conflicts relating to the exploitation of natural resources, and a quarter of the 50 active armed conflicts in 2001 were largely ''motivated'' by resources. One of the underlying tensions between Israel and Syria is access to water. A water expert has recently predicted that, in regions initially experiencing low-level conflict, the risk of escalation to full-scale civil war approximately doubled immediately after a year of abnormally low rainfall.

All of these examples illustrate how armed conflict that is at least partially driven by disputes over natural resources can result in very significant destruction to the natural environment. Not only have recent conflicts in Sierra Leone, the Democratic Republic of Congo and Liberia been fought over natural resources, but the exploitation of those resources for example, timber and diamonds in turn funded the combatants to acquire weapons.

This has given rise to the concept of ''asset wars'', where economic interests in relation to natural resources commercialise and prolong conflict. The misuse of natural resources, such as diamonds, or the scarcity of resources, such as water, serves to fuel the conflict, which often becomes a self-perpetuating process.

Environmental degradation and exploitation can thus be both a cause and a consequence of armed conflict. Internal disputes over scarce resources can give rise to social upheaval and tensions within a country, which may motivate combatants in a conflict to consider ''targeting'' the environment.

Many States now view their environmental concerns, including resource conservation and sustainable development, in ''strategic'' terms. This thinking will only increase as the world quite rightly becomes concerned with the broader state of the global environment, including the disastrous effects of climate change.

Despite all of this evidence, however, environmental damage and exploitation is still largely regarded, as rape once was, as an ''unfortunate but inevitable'' consequence of war. It is, of course, true that war and armed conflict are inherently destructive of the environment, but that is no reason to allow leaders to deliberately or recklessly target the environment in order to achieve their military goals. Just as international law has made great strides forward by classifying rape during armed conflict as a war crime (or even genocide in certain circumstances), a body of standards is developing in relation to the environmental effects of proposed military actions.

But much more needs to be done. The issue is highly politicised but of crucial importance. There is an ongoing need to ''upgrade''' these standards to the level of an international war crime, in the light of the destructive capability of weapons technology. It is increasingly clear that ''crimes against the environment'' need to be enshrined as a part of the mechanisms of international criminal justice, in order to better protect our most cherished assets for future generations.