Wars have a serious impact on the environment, ranging from neglect to deliberate destruction of crops and houses, and as in the case of the American war against the Vietnamese, destruction of forest ecosystems with broad-leaf herbicides which also have adverse effects on human health. Environmental consequences of current and past wars include: hazards from unexploded weapons; physical and biological effects of damage to soil and landscape; and human suffering resulting from the disruption of social systems. The effects would be most devastating in the case of nuclear warfare. The long-term effects of chemical and biological warfare on a large-scale remain to be determined.
Public services are often the first to be interrupted or lost during times of armed conflict, when normal patterns of life are disrupted. Their loss becomes acute, and eventually critical, to the environment and health when the infrastructure, comprising personnel, materials, equipment and buildings, is deliberately destroyed or denied to whole populations.
The main effects of armed hostilities causing misery or death include hunger, disease, dehydration, pest infestations, trauma and mental stress. All weapons cause direct physical damage, but such weapons as land mines can also have secondary effects (collateral damage) on civilian populations and the natural environment. Land mines, trip wires and booby traps also cause considerable difficulties when people try to regain access to buildings, clinics, public health centres, water pumping and treatment stations, sewerage systems and waste disposal sites.
Estimated air emissions from Kuwaiti oil fires in 1991 were 65 megatonnes of carbon. This is more than one percent of the total world emissions from fossil fuel combustion in 1990 (6,000 megatonnes). According to the National Science Foundation of the USA, the 737 burning oil wells were producing 2 million tonnes of carbon dioxide and 5,000 tonnes of soot each day. Regional temperatures were reported to be 10 to 15 degrees Centigrade lower than normal. Grazing animals were dying near Kuwait City from hydrocarbon-contaminated grass. Black rain and acid rain were falling in neighbouring Iran and reports occurred up to 3,500 kilometres distant, including the Indian Himalayas and Bulgaria. Friends of the Earth and Greenpeace claimed that the smoke could influence the temperature of the Indian Ocean, thus affecting monsoon rains and Indian harvests. Concern was also expressed for the effects of acid precipitation and soot on the 2.5 million hectares of semi-arid forest along the Persian Gulf and Sea of Oman. International scientists predicted an increase in lung cancers among Kuwait citizens in one or two decades.
One of the least publicised consequences of the Balkans conflict was the massive release of toxic pollutants into the environment from the destruction of ammunition dumps and civil and military industrial instillations. An explosion in 1992 at an oil refinery at Sisak, south of Zagreb released 95,000 tones of crude oil and other pollutants into the surrounding area. A 500 mile oil slick ran from the refinery down the River Sava into the River Danube, causing major pollution to the Danube Delta. In another incident, the destruction of a chemicals factory at Osijek resulted in the release of over 100 tons of active ingredients for pesticides into the environment which subsequently filtrated into the Drava River, another tributary of the Danube. The amount of polyaromatic hydrocarbons, dioxins, PCBs and other heavy metals released into the environment during the conflict caused significant destruction of wildlife and appeared as health results in people drawing water from the Drava, Sava and Danube Rivers.
Areas of the Falklands were fenced off permanently because clearing the mine fields was not worth the risk and cost involved.
During the 1990s, the European Region experienced the disastrous effects of armed conflicts and serious civil disruption in Albania, Armenia, Azerbaijan, Bosnia and Herzegovina, Croatia, Georgia, the province of Kosovo, the Russian Federation (Chechnya) and Tajikistan.
The war in central Africa fought for five years beginning in 1993 destroyed the regions wildlife. Park officials of the Kahuzi-Biega park in The Democratic Republic of Congo estimated that 100 of the park's 250 lowland gorillas were killed during this conflict. Along with three quarters of the 400 forest elephants alive before the war. Arrested poachers have admitted to killing 20 gorillas and 17 elephants since April 1998. Before 1993 3000 tourists visited the the park each year and their contribution to the economy was vital in building schools roads and water projects for the population around the park. Without the tourists and the war the economy has plummeted, a consequence is that poaching has increased and elephant meat is popular as it is half the price of beef.
Civil conflict and war in Africa also led to significant ecological damage and biodiversity losses in and outside protected areas, as well as to the marginalization of environmental management institutions and conservation programmes. By 1991, the wildlife populations of national parks and reserves in Angola had been reduced by civil war to only 10 per cent of their 1975 levels (Huntley and Matos 1992). Similar losses likely occurred in the Great Lakes region during those years.
Much of Japan's forests were destroyed in World War II. In the former Korea (before separation), forest resources were excessively removed during the last years of Japanese colonial rule and were severely damaged by the Korean War in 1950-53 (OECD 1997). War in Indochina during the 1960s and early 1970s was extremely detrimental: about 2 million ha of forest in Viet Nam were destroyed through bombing and spraying of defoliant (WCMC 1994) and the toxic after-effects of residual dioxin held back forest regeneration for several years, especially in mangrove areas. Similarly, there was substantial loss of forest cover in northern Laos due to bombing during the war (DAI 1995).
In Somalia, warlords sold rights to European firms to dump toxic waste; in a sense, one could consider this toxic warfare.