The story appears on

Page A6

December 3, 2009

GET this page in PDF

Free for subscribers

View shopping cart

Related News

Home » Opinion » Foreign Views

We knew about global warming 150 years ago

ON June 10, 1859, six months before Charles Darwin published his "Origin of Species," the physicist John Tyndall demonstrated a series of experiments at the Royal Institution in London.

The meeting was chaired by Prince Albert. But neither he, nor Tyndall, nor anyone in their distinguished audience could possibly have anticipated the extent to which the experiments' results would preoccupy the world 150 years later.

This month, thousands of people from all over the world, including many heads of state, will gather in Copenhagen to try to forge an agreement to drastically cut atmospheric emissions of an invisible, odorless gas: carbon dioxide.

At the conference's heart are the results of Tyndall's experiments. But the story starts even before Tyndall, with the French genius Joseph Fourier.

An orphan who was educated by monks, Fourier was a professor at the age of 18, and became Napoleon's governor in Egypt before returning to a career in science.

In 1824, Fourier discovered why our planet's climate is so warm - tens of degrees warmer than a simple calculation of its energy balance would suggest. The sun brings heat, and earth radiates heat back into space - but the numbers did not balance.

Fourier realized that gases in our atmosphere trap heat. He called his discovery l'effet de serre - the greenhouse effect. It was Tyndall who then put Fourier's ideas to the test in his laboratory. He proved that some gases absorb radiant heat (today we would say long-wave radiation). One of these gases was CO2.

In 1859, Tyndall described the greenhouse effect in beautifully concise words: "The atmosphere admits of the entrance of solar heat, but checks its exit; and the result is a tendency to accumulate heat at the surface of the planet."

In 1965, an expert report - the first of many - to US President Lyndon B. Johnson warned of global warming:

"By the year 2000, the increase in carbon dioxide will be close to 25 percent. This may be sufficient to produce measurable and perhaps marked changes in climate."

We did not have to wait until 2000 to find these predictions were correct: by the 1980s, global warming became apparent in temperature measurements from weather stations around the world.

In 1988, the Intergovernmental Panel on Climate Change (IPCC) was founded to analyze the issue in more detail, and in 1992 at the Earth Summit in Rio de Janeiro world leaders signed a historic treaty: the Framework Convention on Climate Change.

Unfortunately, little has been achieved in the 17 years since then. In fact, CO2 emissions from fossil fuels were almost 40 percent higher in 2008 relative to 1990. And even the rate at which emissions are increasing is now three times higher than in the 1990s.

Most countries now agree that global warming should be stopped at a maximum of 2 degrees centigrade.

But this has become an extremely tough challenge, as growth in greenhouse-gas emissions and atmospheric stocks accelerated in the years since Rio. That is why Copenhagen is so important: it may well be our last to address climate change before it addresses us.

Tyndall's measurements 150 years ago showed that carbon dioxide traps heat and causes warming. And, 50 years ago, Keeling's measurements showed that CO2 levels are increasing.

In the meantime, earth's climate has been heating up, as predicted. How much more proof do we need before we act?

(The author is professor of physics of the oceans at Potsdam University, Berlin, and department head at the Potsdam Institute for Climate Impact Research. The views are his own. Copyright: Project Syndicate, 2009. www.project-syndicate.org)




 

Copyright © 1999- Shanghai Daily. All rights reserved.Preferably viewed with Internet Explorer 8 or newer browsers.

沪公网安备 31010602000204号

Email this to your friend