Intergovernmental Panel on Climate Change 4th Report

The Intergovernmental Panel on Climate Change (IPCC) has issued its 4th Assessment Report on climate change. The report is a summary for policymakers and will serve as the discussion document for the upcoming Dec 3-14 United Nations Framework Convention on Climate Change (UNFCCC) conference in Bali, Indonesia. The IPCC (formed 1988) and the UNFCCC (formed 1992 at Rio Summit) are part of the United Nations (More). The report shows that human influences have:

• Very likely contributed to sea level rise during the latter half of the 20th century
• Likely contributed to changes in wind patterns, affecting extra-tropical storm tracks and temperature patterns
• Likely increased temperatures of extreme hot nights, cold nights and cold days
• More likely than not increased risk of heat waves, area affected by drought since the 1970s and frequency of heavy precipitation events.

The report also states that:

1) Altered frequencies and intensities of extreme weather (heat waves, heavy
precipitation events, droughts, more severe storms, extreme sea level
events), together with sea level rise, are expected to have mostly adverse
effects on natural and human systems.

2) Anthropogenic warming could lead to some impacts that are abrupt or
irreversible, depending upon the rate and magnitude of the climate change.

3) Anthropogenic warming and sea level rise will continue for centuries due to
the timescales associated with the climate processes and feedbacks, even if GHG
concentrations were to be stabilized.

4) Climate change preferentially selects the poorest and most vulnerable in any
society. (Grist)