That the global climate is warming is unequivocal.
That human emissions of greenhouse gases are causing this warming is considered very likely (90% chance) by the respected International Panel on Climate Change (IPCC) and a majority of scientists working in the field.
The IPCC delivered its Fourth Assessment Report in 2007 and projected that global average surface temperatures will rise within a range from 1.1 to 6.4 degrees by 2100 across several scenarios. Unfortunately, a considerable body of scientific work since the release of this report indicates that we are now tracking in the upper bounds or beyond many of the IPCC projections. For example 'current estimates indicate that ocean warming is about 50% greater than had been previously reported by the IPCC'. (1) Scientists in Europe are seeing direct evidence of climate change in the form of shrinking glaciers, diminishing winter sea ice in the Arctic and measurable shifts in ranges of animal and plant species, to name a few.
The magnitude and speed of climate change will result in degraded ecosystems and threatens to severely test or exceed mankind's ability to adapt. Rising temperatures, altered precipitation patterns, sea level increases, altered bushfire dynamics and extreme weather events will retard economic development and pose increasingly severe threats to agriculture, international security, infrastructure, water security and energy systems.
The climate has warmed and cooled many times in the past and inevitably there will always be some degree of debate and uncertainty over climate trends and drivers. However, the weight of expert opinion and common sense suggests that we to act. And act urgently.
(1) For a more detailed analysis, see, for example, the Synopsis Report from the Climate Change: Global Risks, Challenges and Decisions conference www.climatecongress.ku.dk
The IPCC delivered its Fourth Assessment Report in 2007 and projected that global average surface temperatures will rise within a range from 1.1 to 6.4 degrees by 2100 across several scenarios. Unfortunately, a considerable body of scientific work since the release of this report indicates that we are now tracking in the upper bounds or beyond many of the IPCC projections. For example 'current estimates indicate that ocean warming is about 50% greater than had been previously reported by the IPCC'. 