'Warming of the Climate System Is Unequivocal': Highlights of the Fourth IPCC Assessment Report

By Zhang, Yuwei | UN Chronicle, June 2007 | Go to article overview

'Warming of the Climate System Is Unequivocal': Highlights of the Fourth IPCC Assessment Report


Zhang, Yuwei, UN Chronicle


The Intergovernmental Panel on Climate Change (IPCC) was established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) in 1988 to recognize the problem of potential global climate change. IPCC has three Working Groups and a Task Force and continues to provide scientific, technical and socio-economic advice to the world community, in particular to the Parties to the United Nations Framework Convention on Climate Change (UNFCCC).

The reports by the three IPCC Working Groups provide a comprehensive assessment of the current state of knowledge on climate change and contribute to the Panel's Fourth Assessment Report, Climate Change 2007, which is coming out in 2007. With 450 lead authors and 800 contributors, the Assessment Report includes findings from more than 2,500 scientists from over 130 countries, summing up the last six years of research.

Building upon past IPCC assessments, Working Group I reports on progress in understanding the human and natural drivers of climate change. Working Group II reviews the current understanding of the climate change impacts on natural, managed and human systems, as well as the vulnerability of socio-economic and natural systems to climate change. Working Group III focuses on the scientific, technological, environmental and socio-economic aspects of mitigation of climate change and the options for limiting greenhouse gas emissions.

THE PHYSICAL SCIENCE BASIS

Human and Natural Drivers of Climate Change

* Carbon dioxide (C[O.sub.2]) is the most important anthropogenic greenhouse gas (GHG). The global atmospheric concentration of C[O.sub.2] has increased from a pre-industrial value of about 280 to 379 parts per million in 2005, exceeding by far the natural range over the last 650,000 years (180 to 300 ppm), as determined from ice cores. The annual C[O.sub.2] concentration growth rate was larger over the period 1995-2005.

Warming of the climate system is unequivocal. This can be found in evidence of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising sea levels.

* Eleven of the last 12 years of 1995 to 2006 rank among the 12 warmest in the instrumental record of global surface temperature since 1850.

* Observations since 1961 show that the average temperature of the ocean has increased to at least 3,000 metres in depth and has been absorbing more than 80 per cent of the heat added to the climate system; such warming causes seawater to expand and contributes to sea-level rise.

* Mountain glaciers and snow cover have declined on average in both hemispheres. Widespread decreases in glaciers and ice caps have contributed to sea-level rise; the global sea level rose at an average rate of 1.8 mm per year from 1961 to 2003 and the rate was faster over the period 1993-2003.

At continental, regional and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in Arctic temperatures and ice, widespread changes in precipitation, ocean salinity, wind patterns and aspects of extreme weather conditions, such as droughts, heavy precipitation, heatwaves and the intensity of tropical cyclones like hurricanes and typhoons.

* Average Arctic temperature increased at almost twice the global average rate in the past 100 years.

* Temperatures at the top of the permafrost layer in the Arctic have generally increased since the 1980s.

* More intense and longer droughts have been observed over wider areas since the 1970s, particularly in the tropics and subtropics. Changes in sea surface temperatures and wind patterns, and decreased snowpack and snow cover have also been linked to droughts.

* Widespread changes in extreme temperatures have been observed over the last 50 years. Temperature extremes are likely to have increased due to anthropogenic forces.

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

'Warming of the Climate System Is Unequivocal': Highlights of the Fourth IPCC Assessment Report
Settings

Settings

Typeface
Text size Smaller Larger
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.