War and environmental law

War can heavily damage the environment, and warring countries often place operational requirements ahead of environmental concerns for the duration of the war. Some international law is designed to limit this environmental harm.
Environmental impact of war.
War and military activities have obvious detrimental impacts on the environment. Weaponry, troop movements, land mines, creation and destruction of buildings, destruction of forests by defoliation or general military usage, poisoning of water sources, target-shooting of animals for practice, consumption of endangered species out of desperation etc., are just some of the examples of how both war and peacetime military activities (such as training, base construction, and transportation of weaponry) harm the environment.
Law.
From a legal standpoint, environmental protection during times of war and military activities is addressed partially by international environmental law. Further sources are also found in areas of law such as general international law, the laws of war, human rights law and local laws of each affected country. However, this article is chiefly focused on the environment and as soon as two countries are battling it out, the issue becomes one of international concern. Thus, international environmental law that the United Nations Security Council enforces is the focus here.
The law of armed conflict is not very well developed in comparison to other areas of international law. Only the United Nations Security Council has the authority and the jurisdiction to regulate its development and implementation, or to monitor its observance.
UN treaties.
Several United Nations treaties, including the Fourth Geneva Convention, the 1972 World Heritage Convention and the 1977 Environmental Modification Convention have provisions to limit the environmental impacts of war or military activities.
1977 Environmental Modification Convention.
The Environmental Modification Conventionis an international treaty prohibiting the military or other hostile use of environmental modification techniques having widespread, long-lasting or severe effects. The Convention bans weather warfare, which is the use of weather modification techniques for the purposes of inducing damage or destruction. This treaty is in force and has been ratified (accepted as binding) by leading military powers.
Customary international law.
Customary international law also has something to say about protection of the environment during times of armed conflict and military activities.
"States shall ... respect international law providing protection for the environment in times of armed conflict and cooperate in its further development, as necessary."
Thermonuclear war.
The International Court of Justice advisory opinion on the Legality of the Threat or Use of Nuclear Weapons considered the environment as a minor issue in regard to the legality of thermonuclear war but it did not find all thermonuclear war to be prohibited.
Organisations.
The international organisations with environmental mandates may be called upon during times of armed conflict to assist with mediating or remedying damage caused by armed conflict. Such agencies as the UN Environment Programme, the World Health Organization and the International Maritime Organization will be of relevance here. The UN Security Council has also demonstrated environmental concern in deliberations on recent conflicts, for example, during the 1991 Gulf War. UNEP and IMO were also involved in this conflict, attempting to remedy the most serious of the environmental impacts.