Three of Sweden's national parks lie completely or partially in Västra Götaland County. Tresticklan in Dals-Ed Municipality became a national park in 1996. Djurö in Mariestad Municipality became a national park in 1991. Tiveden in Karlsborg Municipality (also Laxå Municipality in Örebro County) became a national park in 1983.
As technology has developed, mankind has begun to influence the environment in such a way that the natural ecocycles have been disturbed. Acidification is primarily accelerated by fallout of sulphurous compounds. Carbon dioxide increases the greenhouse effect. Together with water vapour and certain other gases, carbon dioxide absorbs heat radiation. This does not prevent the heat from sunlight from reaching the earth's surface, but it does effectively prevent heat radiation from the earth from dispersing into space.