Causes of Global Change
In the past, the main drivers of global change have been solar variation, plate tectonics, volcanism, proliferation and abatement of life, meteorite impact, resource depletion, changes in Earth’s orbit around the sun and changes in the tilt of Earth on its axis. There is overwhelming evidence that now the main driver of planetary-scale change, or global change, is the growing human population’s demand for energy, food, goods, services and information, and its disposal of its waste products. In the last 250 years, global change has caused climate change, widespread species extinctions, fish-stock collapse, desertification, ocean acidification, ozone depletion, pollution, and other large-scale shifts.
Scientists working on the International Geosphere-Biosphere Programme have said that Earth is now operating in a “no analogue” state. Measurements of Earth system processes, past and present, have led to the conclusion that the planet has moved well outside the range of natural variability in the last half million years at least. Homo sapiens have been around for about 200,000 years.
What this means for the planet and society remains unclear. But, in the last 20 years there has been an enormous international research effort to understand global change and the Earth system. An aim of this research is to work out if there are planetary boundaries and are we approaching them. Scientists, international governmental organizations and lobbying organizations like World Wide Fund for Nature argue that current consumption levels, particularly in developed countries, are not sustainable because there is a very real danger they will push the planet into a new state. What this new state might look like is still being debated, but sea levels are likely to rise several meters, the pH of the oceans, a measure of its acidity, is likely to drop farther than it has in 20 million years, and global atmospheric and ocean circulations may shift markedly. The major cycles – carbon, nitrogen, sulfur, phosphorus, water – and other important parameters would alter, bringing drought to some places, floods to others. Governments will no longer be able to take for granted the relative environmental stability that has allowed human society to flourish and led to rapid globalization. Most of the population of the planet will be affected. The re-insurance industry is already taking measures to protect its interests and maximize profits as turbulent times approach.
Read more about this topic: Global Change
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