Bushfires intensifying as they feed climate change, scientist warns

  Bushfires intensifying as they feed climate change, scientist warns

24 April 2009

published by www.abc.net.au

Global — Scientists are warning that bushfires will get more intense because they’re feeding climate change.

The warning is coming from a professor at the University of Tasmania who’s been studying bushfires for 30 years.

Today professor David Bowman has had a paper published in the journal Science.

Felicity Ogilvie spoke to David Bowman in our Hobart studio.

DAVID BOWMAN: Because of industrialisation and global climate change, we are seeing evidence of increased fire activity.

Now the problem is that we can all understand that climate affects fire. What has been not understood is that fire can affect climate through the feedback mechanisms of releasing atmospheric pollutants, changing the reflectants of the earth’s surface, changing the way ecosystems behave and committing very large quantities of carbon dioxide into the atmosphere.

FELICITY OGILVIE: How are these wildfires affecting the earth’s climate?

DAVID BOWMAN: We’ve calculated just from the deforestation fires alone, the fires that have been used to destroy forests since the industrial revolution account for about one-fifth of all of the CO2 which has been committed to the atmosphere. So that’s a very significant component in global warming.

Now we have assumed that the fires in the natural vegetation are in equilibrium. That is a very conservative assumption. All of the evidence now is that because of the rapidly accelerating rate of global climate change, we are seeing more fire activity, more extreme fire weather, more extreme fires all over the world.

Fires are now beginning to be like a rash on this planet. The danger is that if these fires keep up this tempo and global warming continues, it is going to be extremely difficult for the vegetation that has been destroyed in these forests to regrow back to reabsorb all of the carbon which has been emitted into the atmosphere. That will result in a feedback.

FELICITY OGILVIE: So are you saying that the intensity and size of the fires is increasing and is that because of climate change?

DAVID BOWMAN: The evidence in the west of the United States is that the fire seasons are now growing bigger, the springs are starting earlier, the snowpack is earlier so very detailed analysis where we are seeing a huge increase in the size and the frequency of fire activity.

We haven’t done an equivalent analysis here in Australia but I would be certain that the results would be consistent with that.

What happened in the Victorian fires, just to help your listeners understand, is that we have a fire danger index which maxes out at about 100. Those fires were maxing out at almost 200.

The fire behaviour just wasn’t harmonising with how people would predict fires to behave. They were extreme.

FELICITY OGILVIE: What happened in Victoria with those extreme fires now that the climate is changing – should we expect that to become the norm now?

DAVID BOWMAN: Absolutely. The huge issue for Australians is that we are now, must understand those catastrophes not to be one-offs, not to be freaks of nature but potentially to become a more standard feature of our environment until we get a grip on global warming and bring down the temperature because basically this is going to be driven, more extreme fire weather is a certainty as we increase the temperature of this planet.

FELICITY OGILVIE: How can the temperatures be brought down if these extreme wildfires are adding to climate change?

DAVID BOWMAN: Well, that underscores one of the extremely important aspects of this paper that we need to get a better understanding of the rate of potential change.

We have got to understand increased bushfire activity as a direct consequence of uncontrolled climate change. This is a very good reason for Australia to do everything we possibly can to bring down the global temperature, to control carbon emissions and other gases which are resulting in the warming of the planet.

FELICITY OGILVIE: And how do you hope that your findings about fire will be used in the future to predict climate change?

DAVID BOWMAN: What we are hoping is that we stimulate the science community, certainly the global change community to think about fire in the earth’s system and we are actually urging the IPCC in their next report or the report after that to actually start dedicating chapters to fire in the earth’s system because currently the IPCC reports, fire is a cameo. It’s all over the place. It is peppered everywhere but it doesn’t get an opportunity to be thought about in its own right as a potent feedback and also a very fundamental feature of our planet.

PETER CAVE: Professor David Bowman speaking to Felicity Ogilvie.

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