Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New report presents strongest evidence yet of human link to global warming

Evidence presented in the first phase of the Intergovernmental Panel on Climate Change's 4th Assessment Report, released today in Paris, paints the clearest picture yet that human-derived greenhouse gases are playing a significant role in observed global warming, says a Duke University scientist who co-authored one of the report's main chapters.

"We are now seeing, not merely predicting, effects of greenhouse warming on a scale and in ways that were not observable before," said Gabriele Hegerl, associate research professor at Duke's Nicholas School of the Environment and Earth Sciences, who also co-authored a summary of the report for policymakers.

"When you look at the changes in temperature, circulation, ocean warming, arctic sea ice reduction and glacial retreat together, it paints a much clearer picture that external drivers, particularly greenhouse gases, are playing a key role," she said. "As a result, we can be much more confident that 20th century climate changes were not just linked to natural variability."

Hegerl was a coordinating lead author of the IPCC report's chapter on "Understanding and Attributing Climate Change." Francis Zwiers of the Canadian Centre of Climate Modeling and Analysis was also a coordinating lead author of the chapter.

IPCC assessment reports are issued every five to six years to provide a comprehensive review of the current state of knowledge on climate change. The 2007 report will be issued in four phases during the year. The first phase, released today in Paris, focuses on the physical evidence of global change.

THE IPCC operates under the auspices of the United Nations Environmental Programme and the World Meteorological Organization and draws on the expertise of about 2,500 scientists worldwide.

Hegerl and her chapter's team of co-authors were charged with reviewing the evidence of changes observed so far and assessing which changes can be attributed to greenhouse gas increases and other external influences on climate. In the chapter, they look at the actual measurements of climate and weather changes and compare them with predictions made for the 20th century by sophisticated computer models.

"We've studied improved observations from land, sea and space, as well as better temperature reconstructions covering the last 1,000 years," Hegerl said. By comparing observation against modeled projections, she says scientists are gaining a better sense of which external climate influences have been important.

"Understanding the observations is really what this all is about. For instance, looking at the patterns of change in 20th-century temperatures, we can now distinguish between changes caused by greenhouse gases, man-made aerosols, variability in solar radiation and major volcanic eruptions," Hegerl said. "We can also better understand which changes in the more distant past were caused by external influences of climate, such as volcanic eruptions, and how strong the variability of the climate system is.

"One of the most fascinating things is that we see that changes have already happened or are happening now in more climate variables than just temperature," Hegerl added. "For instance, there have been observed changes in ocean temperatures, global rainfall and in circulation of the atmosphere. We now are beginning to understand that these changes occur at least partly in response to anthropogenic influences on climate. This allows us to better evaluate model simulations, which do simulate aspects of these changes, although not as successfully as they simulate changes in temperature," she said.

"There are still things, like ice-sheet melting, that the models don't do very well yet. But overall, the predictions and uncertainty ranges of future climate change are becoming much better understood and much more credible," Hegerl said.

The IPCC report "hits the nail squarely on the head," she said. "It gives a very balanced view of the evidence for climate change, predictions of future change, and the remaining uncertainties, and it draws input from very large number of scientists worldwide."

The report went through several phases of review, giving individual experts and governments opportunity to comment. "There were many steps that ensure that the report is both scientifically rigorous and balanced," Hegerl said.

"The information in the report will be very important to develop effective policies to address global climate change and to prepare for the change that is coming our way," she said.

Tim Lucas | EurekAlert!
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>