Scientists from all over the world have signed their name to an "Amsterdam Declaration" on the state of our planet and the urgent need for action.
The world faces significant environmental problems that encompass and go way beyond global warming, they say.
"The accelerating human transformation of the Earth's environment is not sustainable. Therefore the business-as-usual option of dealing with the Earth is not an option," the declaration states.
Because the Earth behaves as a single integrated system, climate change cannot be separated from changes in biodiversity, vegetation, land cover and ocean circulation. Climate change is a component of global change. Even if we were to completely stop emitting greenhouse gases tomorrow, there would still be many profound challenges facing us.
The declaration points out that humans are now such a dominant force on the planet and are making such dramatic changes to all aspects of the physical environment that the Earth system is beginning to respond. Though it is tempting to think that the Earth will continue to respond in gradual and predictable ways, there is now mounting evidence that some changes may occur abruptly and without warning.
"These issues are not simply interrelated environmental issues but are development issues threatening our ability to meet the human needs of adequate food, clean water, a healthy environment and safe shelter," said Robert Watson, Chair of the Intergovernmental Panel on Climate Change and a participant at the conference.
"The pioneering environmental Stockholm conference was held in 1972. Now, almost 30 years later, it is very timely that we now have an Amsterdam Declaration that summarises the challenges facing the globe and helps set the research agenda for the coming decades," said Berrien Moore III, Chair of the International Geosphere-Biosphere Programme.
Some of the major changes occurring around the globe include:
· Nearly 50% of the land surface has been transformed by direct human action, with significant consequences for biodiversity, nutrient cycling, soil structure and biology, and climate. Most of the remainder has been affected to some extent by human activities and only about 5% is pristine.
· Extinction rates are increasing sharply in marine and terrestrial ecosystems around the world; we are now in the midst of the sixth great extinction event in Earth's history, but the first one caused by the activities of a single biological species.
· More than half of all accessible freshwater is used directly or indirectly by humankind, and underground water resources are being depleted rapidly in many areas. Rivers take an average of 45 days longer to reach the ocean than they did 50 years ago and many currently don't even reach the sea for extended periods.
· Coastal and marine habitats are being dramatically altered; 50% of mangroves have been removed and wetlands have shrunk by one-half;
· More nitrogen is now fixed synthetically and applied as fertilizers in agriculture than is fixed naturally in all terrestrial ecosystems.
· The concentrations of several climatically important greenhouse gases such as carbon dioxide and methane have substantially increased in the atmosphere;
· About 22% of recognized marine fisheries are overexploited or already depleted, and 44% more are at their limit of exploitation;
It is not a matter of deciding which is the most important issue. All these changes interact with cumulative and follow-on effects. "Global Change is real and is happening now," states the Declaration.
The conference was held from 10-13 July in Amsterdam and was attended by 1400 global change scientists from over 100 countries and all continents of the world.
Download a copy of the declaration at www.sciconf.igbp.kva.se