Clear The Air News Blog Rotating Header Image

Magic Number 350

Updated on Jul 04, 2008 – SCMP

Scientists, environmentalists and politicians have got the message about global warming out loud and clear. We know that if we pollute less, temperatures will fall; glaciers and polar ice will then stop melting, sea levels will drop and there will be fewer severe climate patterns. But not so widely known is what we have to aim for to achieve this.

The 1997 Kyoto Protocol on climate change generally puts this target at a reduction of 10 per cent of 1990 carbon dioxide emission levels. Each country has a different figure. Few in the world have an inkling of just exactly what this might be. With greenhouse gas emissions ever-rising, the number is constantly changing.

Nasa climate scientist James Hansen, who tuned us in to global warming and the need to do something about it 20 years ago, has been looking for an answer for some time. He revealed one that we can all relate to and aim for, speaking at the American Geophysical Union meeting in San Francisco last December. It is 350.

This, specifically, is 350 parts per million of carbon dioxide in the atmosphere. Dr Hansen says this is the absolute upper boundary at which the Earth can be safe from global warming. If we can keep it lower, then all the better.

We should be alarmed. The foremost measurement station for atmospheric readings of carbon dioxide, the Mauna Loa Observatory, 3,397 metres up a volcano in Hawaii, puts the latest figure at 387 parts per million – 2 ppm more than when Dr Hansen gave his presentation. Based on his assertion at the time, this means that our climate patterns are fast unravelling and will continue to do so until the number is back down to 350.

Our leaders are telling us that global warming is a problem and advising what to do about it. The big picture is not so clear, though: Do we cut by a certain percentage, or reduce by half, or decrease to previous levels, the amount of carbon dioxide we pour into the atmosphere? We would do much better to follow the preaching of American environmentalist and author Bill McKibben and express how much over the minimum level we are, as with temperatures.

McKibben is spearheading the 350 movement, which has tasked itself with getting the number into the minds and actions of as many people as possible across the world, using the website He told me from Beijing on Wednesday that it was essential that those drafting the successor pact to Kyoto had the number firmly in mind during negotiations, which are to conclude in Copenhagen in December next year.

The campaign is barely four months old, but already significant achievements can be claimed. US Democratic presidential candidate Senator Barak Obama has already signed up; so, too, has his former challenger, Senator Hillary Rodham Clinton. The organisers of the Tallberg Forum, an international meeting on poverty and development attended by a number of present and past world leaders in Sweden last month, took out full-page advertisements using the number in some of the world’s most prestigious newspapers. In early April, 350 bicycle riders took to the streets of Salt Lake City in the US to promote the idea.

McKibben, who in the past two weeks has been in Canada, Italy, Trinidad and Sweden, wants similar events themed around the number 350 to push the cause. Anything will do to get the message out: a 350 marked in organic paint on a shrinking glacier, or a banner with the number hanging prominently down a building. The one he seems to quote the most is 350 churches ringing their bells 350 times, although he would be happy to see temporary “350” tattoos on people’s foreheads. The more people who see the number and ask what it means, the more who will know of their obligations.

There can be no better way of getting as many people as possible involved in fighting global warming. As McKibben explained, the situation was akin to a patient with high cholesterol being told by a doctor that a heart attack or stroke was in the offing unless action was taken. The world already has those danger signs – and only by getting to the 350 safety zone can survival be assured.

Peter Kammerer is the Post’s foreign editor.

Leave a Reply

Your email address will not be published. Required fields are marked *