Global change

Global change refers to planetary-scale changes in the Earth system. The system consists of the land, oceans, atmosphere, polar regions, life, the planet's natural cycles and deep Earth processes. These constituent parts influence one another. The Earth system now includes human society, so global change also refers to large-scale changes in society. Global change refers to planetary-scale changes in the Earth system. The system consists of the land, oceans, atmosphere, polar regions, life, the planet's natural cycles and deep Earth processes. These constituent parts influence one another. The Earth system now includes human society, so global change also refers to large-scale changes in society. More completely, the term 'global change' encompasses: population, climate, the economy, resource use, energy development, transport, communication, land use and land cover, urbanization, globalization, atmospheric circulation, ocean circulation, the carbon cycle, the nitrogen cycle, the water cycle and other cycles, sea ice loss, sea-level rise, food webs, biological diversity, pollution, health, over fishing, and more. In 1980, a group of scientists led by Swedish meteorologist Bert Bolin set up an international program called the World Climate Research Programme (WCRP), to determine whether the climate was changing, whether climate could be predicted and whether humans were in some way responsible for the change. The programme was sponsored by the World Meteorological Organization and the International Council for Science (ICSU). As time went on, there was a growing realisation that climate change was one part of a larger phenomenon, global change. In 1987, a team of researchers, led again by Bert Bolin, James McCarthy, Paul Crutzen, H. Oeschger and others, successfully argued for an international research programme to investigate global change. This programme, sponsored by ICSU, is the International Geosphere-Biosphere Programme (IGBP). The programme has eight projects investigating different parts of the Earth system and links between them. IGBP, WCRP and a third programme, the International Human Dimensions Programme (IHDP, founded in 1996), spearheaded a landmark science conference held in Amsterdam in 2001. The conference, Challenges of a Changing Earth: Global Change Open Science Conference, led to the Amsterdam Declaration which stated, 'In addition to the threat of significant climate change, there is growing concern over the ever-increasing human modification of other aspects of the global environment and the consequent implications for human well-being. Basic goods and services supplied by the planetary life support system, such as food, water, clean air and an environment conducive to human health, are being affected increasingly by global change.' The declaration goes on to say, 'The international global change programmes urge governments, public and private institutions and people of the world to agree that an ethical framework for global stewardship and strategies for Earth System management are urgently needed.' Many nations now have their own global change programmes and institutes, for example the US Global Change Research Program and the UK's Quantifying and Understanding the Earth System (QUEST) programme. And since the Amsterdam conference another international programme focusing on biodiversity has been set up, DIVERSITAS. These programmes form the Earth System Science Partnership. In 2012, these international programmes held another major science conference in London, Planet Under Pressure: new knowledge towards solutions. 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.