Stronger evidence for human origin of global warming

July 30, 2007

A recent statistical analysis strengthens evidence that human activities are causing world temperatures to rise. Most climate change scientists model Earth systems from the ground up, attempting to account for all climate driving forces. Unfortunately, small changes in the models can lead to a broad range of outcomes, inviting debate over the actual causes of climate change.

Physicist Pablo F. Verdes of the Heidelberg Academy of Sciences in Germany has found a way to avoid the subjective flaws of climate models by applying sophisticated analysis techniques to data from the past hundred and fifty years.

The approach mathematically stitches together known facts about the global climate into a more objective and coherent picture.

Verdes, now at Novartis Pharma, examined data on temperature anomalies, the strength of the radiation emitted from the Sun, and volcanic activity. The relatively recent increases in solar radiation, combined with reduced volcanic activity, contribute to the increase in world temperatures. However, Verdes' analysis demonstrates that these natural causes do not completely explain the observed warming.

Verdes calculated the amount of non-natural influence required to match the increases in temperature observed in the last 150 years. He plotted the influence over time. Then, he compared it to the evolution of greenhouse gasses, taking into account the cooling due to aerosols. With allowances for error, he found that influences attributable to greenhouse gasses mirror the graph of non-natural influence needed to explain the observed temperature increase of recent decades.

His research shows that, if you look at global warming as a puzzle, and you put together the natural factors such as increased solar radiation and reduced volcanic activity, a hole remains. The human factors of greenhouse gas and aerosol emission complete the picture.

Citation: Pablo F. Verdes, Physical Review Letters (forthcoming article)

Source: American Physical Society

Explore further: Distant volcanic eruptions foster saguaro cacti baby booms

Related Stories

Distant volcanic eruptions foster saguaro cacti baby booms

July 25, 2016

One hundred and thirty years ago, the volcano Krakatoa erupted in what is now Indonesia, unleashing a cataclysm locally and years of cool temperatures and rain globally. On the far side of the world, a bumper crop of saguaro ...

Did cirrus clouds help keep early Mars warm and wet?

August 16, 2016

Many features on the surface of Mars hint at the presence of liquid water in the past. These range from the Valles Marineris, a 4,000 km long and 7 km deep system of canyons, to the tiny hematite spherules called "blueberries". ...

Recommended for you

Engineers discover a high-speed nano-avalanche

August 24, 2016

Charles McLaren, a doctoral student in materials science and engineering at Lehigh University, arrived last fall for his semester of research at the University of Marburg in Germany with his language skills significantly ...

Funneling fundamental particles

August 24, 2016

Neutrinos are tricky. Although trillions of these harmless, neutral particles pass through us every second, they interact so rarely with matter that, to study them, scientists send a beam of neutrinos to giant detectors. ...

Understanding nature's patterns with plasmas

August 23, 2016

Patterns abound in nature, from zebra stripes and leopard spots to honeycombs and bands of clouds. Somehow, these patterns form and organize all by themselves. To better understand how, researchers have now created a new ...

NIST's compact gyroscope may turn heads

August 23, 2016

Shrink rays may exist only in science fiction, but similar effects are at work in the real world at the National Institute of Standards and Technology (NIST).

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.