The Millennium Ecosystem Assessment, published in 2005, reported that, over the previous 50 years, humans have changed ecosystems more rapidly and extensively than in any comparable period of time. Those assessments have painted a consistently negative picture of the state of the global environment and of the impacts of human activities.

Many assessments of global environmental change have been produced since the 1980s. The sheer number, magnitude and complexity of these issues can seem overwhelming and some commentators have argued that they amount to a cumulative, sustained human impact on the environment that has profoundly transformed the surface of the Earth. Numerous environmental changes have been identified as issues of global concern: desertification the depletion of fuelwood the destruction of tropical rainforest and rapid declines in forest cover the modification of coastal ecosystems the reduced availability and quality of drinking water the depletion of soil resources the over-exploitation of fisheries food shortages species extinction and the loss of biodiversity stratospheric ozone depletion rapidly rising levels of fossil fuel and demand for energy supplies and climate change. Those efforts have been prompted by widespread concerns that the pace and extent of development in many parts of the world have far outstripped the capacity of natural ecosystems to absorb the impacts of human activities. Since then, and particularly since the 1980s, considerable scientific efforts have been made to investigate and to document the state of the global environment and the nature of global environmental change. Concerns about the state of the environment have deep historical roots, but those concerns came to prominence during the 1960s following the publication (in 1962) of a seminal book by Rachel Carson, Silent Spring, and the emergence of the modern environmentalist movement in some countries (Carson 1962). Together with the widening realisation of the problem of poverty, there has been an increasing awareness of the existence of a second global crisis: that of environmental degradation. List what you consider to be the most important global environmental issues.

Unep geo 5 report