For thousands of years, hunting and over-fishing were the main direct threats to the Earth’s species, but since the mid-1900:s biotope transformation through changes in land use have become a bigger threat, at least for all terrestrial species. It is estimated that 40 % of the Earth’s land surface is now used for agriculture or grazing, 64 million kilometres of roads run across all continents, and 129 million hectares of forest have disappeared since 1990. Deforestation is still continuing at a rate of 74,400 square kilometres, or 0.45 %, a year. Less than 40% of all rivers flow freely without dams. In the seas and oceans the primary threat is still over-exploitation. This, however, is changing as oceans come to be used in more far-reaching ways. Many fishing techniques alter marine environments, for example bottom trawling that has already affected 50 million square kilometres of ocean floor. Invasive alien species, pollution and climate change are also serious direct threats, but fewer species are affected by them than by biotope destruction and over-exploitation.
Many people consider climate change to be the overriding threat to the species’ survival. We have not reached that point yet but 19 % of the endangered species studied are already today affected by changes in climate. Observed impacts on animals and plants include changed behaviours such as food-seeking habits and migration patterns, reduced survival and reproduction, local extinctions and changes in the extent of habitat. The effects are most evident in the Arctic, where the polar bear, walrus, narwhal and ivory gull are dependent on ice and snow, but the impact is likely to be worse in the tropics, where many species are adapted to a narrow climatic range (see the box on corals).
Almost all species are exposed to more than one direct threat. A clear example are the sea turtles. The effects of different threats can interact synergistically, which means that the total impact is greater than just the sum of the effects of various threats. These synergies are probably more the norm than the exception for endangered species. The most common combinations of different threats are related to habitat loss and any of a variety of disturbances in the form of hunting, fire, invasive species and pollution. By far the most harmful is the combination of biotope loss and over-exploitation through hunting, fishing or gathering.
The driving forces behind the direct threats, can be found primarily in human population growth, unregulated markets, socio-economic development, technology development, culture and values, and governance. Anthropogenic driving forces are becoming increasingly stronger and more diverse and are growing in scale from local to global.
At the time of writing (29th October) there are 7,577,568,000 people on the planet. The rate of increase has declined slightly since the 1970:s but forecasts say that by 2050 the figure will have risen to 9.8 billion, or about 2.2 billion more than today. Mankind already uses 25-50 % of the planet’s primary production. Today’s poor want to raise their standard of living, and the rich continue to raise theirs. The additional 2.2 billion will probably also want to live a good life. This will cost the ecosystems even more, in the form of food, water, raw materials, energy and land.
One way to measure human consumption of renewable resources is through the ecological footprint every person makes in relation to the Earth’s capacity to produce these resources. The common currency is global hectare (gha), that is to say the surface area required to produce the resources that humans consume. In 2012, the Earth’s total bio-capacity was 12.2 billion gha, or 1.7 gha per person. Humanity’s total footprint was 20.1 billion gha, or 2.8 gha per person. Our consumption is thus far from sustainable. This means that we are constantly depleting the capital, which over time will also run out. In Sweden we exceed 7 gha/person, as do the United States, Canada, Belgium, Oman and Australia. Countries below 1.7 gha, which is the limit for sustainability, include India, Indonesia and most countries in tropical Africa. Global trade, however, means that the effects of the footprint are not limited to the country where the consumers live. The Swedish ecological footprint affects the entire earth, not least through imports of fossil fuels.
The global economic system has not in any serious manner taken into account the value of ecosystem services. The notion that economic growth is independent of the environment, health, and that the economy can continue to grow indefinitely, is a dangerous delusion. Treating all ecosystem services as commodities, however, is not a solution. Subjecting the ecosystems to the same requirements and risks that commodities and businesses are subjected to in a market economy will not lead to sustainable use. Globalisation intensifies these risks.
International trade is driving the threats to biodiversity in developing countries. In a study . In a study of international trade effects on biodiversity, the threats to 6,964 species of animal were linked to 15,000 commodities produced in 187 countries, and 5 billion supply chains were tracked and graded by impact on biodiversity in the country of origin. Thirty per cent of the identified threats to biodiversity are driven by international trade. Coffee from Latin America, soy and meat from Brazil, forest products and fish from Papua New Guinea, palm oil from Indonesia and Malaysia, and aquarium fish from Viet Nam are examples of global commercial products that cause threats to biological diversity. The United States, Japan, Germany, France, the UK, Italy, Spain, South Korea and Canada each export between 100 and 1,000 threats (number of species times number of threats per species). Indonesia, Madagascar, Papua New Guinea, Malaysia, the Republic of the Philippines, Sri Lanka, Thailand several other countries ‘import’ 100-200 threats per country. The footprint made by the biggest “exporters” of threats is larger abroad than in the country itself. The reason for this is often that these countries have an environmental policy that prohibits hazardous production at home; products are instead imported from other countries and the threats to biodiversity that the production of these goods entails are thereby so to say exported.
None of the major threats have been averted on a global scale. On the contrary, all of them are showing an increasing trend, and new threats have emerged, first and foremost climate change. The goals for biological diversity in the Biodiversity Convention’s Aichi Biodiversity Targets up to 2020 and Sustainable Development Goals up to 2030 will not be realised if present trends continue. Projections of agricultural expansion up to 2100 indicate that large areas of Latin America, Africa and South Asia will be transformed from natural forests into arable land and pasture. This will for example affect 75 % of all primates and eliminate 68 % of the area on which the primates live today. The Climate Panel (IPCC) estimates that 20-30 % of all species will be endangered if temperatures rise more than 2-3 degrees above pre-industrial levels. Climate change will pose an increasing threat to biodiversity, but human population growth and economic development will also lead to intensification of existing threats like over-exploitation and land use.