Once a month Mona Blaber will use this new column to look at climate change and how individuals and families can help make a difference.

Ask Tim Flannery whether he should be referred to as a paleontologist, zoologist or mammalogist, and he chooses "environmental historian."

That's fitting, since his climate-change primer The Weather Makers reads as a history of Earth's climate from 700 million years ago to the present, starring a fish whose habitat has been reduced to a single coral head, a frog that nurtures its tadpoles in its stomach and a selection of scientists, politicians and CEOs. It's made a splash worldwide as a comprehensive layman's explanation of the science linking rising global temperatures to the rising levels of greenhouse gases emitted by burning fossil fuels. Mogul Richard Branson credits The Weather Makers with helping convince him to invest his billions in developing alternative fuels.

Flannery, a professor at Australia's Macquarie University, has discovered 30 species of mammals and made a number of significant fossil discoveries. His previous books include The Future Eaters, an ecological history of Australia that made a huge impact in his native land. But about a decade ago, his focus shifted to climate change.

"By the late 1990s, the science was looking so dismal. If you read the major scientific weeklies such as Nature and Science, you could see this emerging picture that this was becoming a very, very substantial issue," he says.

An outspoken activist, Flannery has criticized the U.S. and Australian governments for refusing to ratify the Kyoto Protocol. He's drawn fire himself for some of his proposals and positions — unlike many environmentalists, for example, he refuses to dismiss nuclear energy as part of the transition from carbon-emitting energy sources. But his mission to increase public awareness seems to be paying off: The Weather Makers remains among Amazon's best-selling titles on climate change, and in January, Flannery was named 2007 Australian of the Year. Prime Minister John Howard, who has often been at odds with Flannery, presented the award, saying, "He has encouraged Australians into new ways of thinking about our environmental history and future ecological challenges."

Flannery will discuss climate issues with Amy Goodman at the Lensic Center for the Performing Arts at 7 p.m. Wednesday as part of the Lannan Foundation's Readings and Conversations series. He spoke with The New Mexican from his home in Sydney.

Question: You paint a pretty grim picture for much of The Weather Makers, but at its conclusion you're hopeful. That was in 2005. Has your perspective changed for the better or worse since then?

Answer: Could I just say that you say it's a grim read, but it is actually a very objective read of the science as it is published in the world's leading journals. So that is really as objective a read as you could get as of 2005. I really did work hard not to make it alarmist and not to be putting in disreputable, highly hypothetical stuff.

Question: But it's worrisome.

Answer: It is extremely worrisome. Next month the Intergovernmental Panel on Climate Change will produce their Synthesis Report, and that has even worse news. [See sidebar]. So the science is getting more dire. We now know that there's enough greenhouse gas in the atmosphere already to carry a high risk of probability of dangerous climate change. That's a 20-percent-plus risk. So we're already facing that situation and we had hoped that was a little bit further out. When you're dealing with a problem like climate change, we're working with timelines that are not human-made. They're dictated by the biosphere, so our actions have to be equally tough. Thankfully, some people are producing plans which give us a reasonable chance of avoiding dangerous climate change, and foremost among them is
Gov. Schwarzenegger in California, who has put exactly the right targets in place and is pursuing that whole issue with vigor.

Question: He's doing that in California; is that level of reductions (to 1990 levels of
carbon emissions by 2020, and 80 percent below them by 2050), if they're able to achieve them, what is needed worldwide?

Answer: It is. We need 80 percent plus in the next 40 years. What that means is we won't be able to be using fossil fuels as we are today 40 years from now, so no more oil, no more gas — or very little anyway — and no more coal unless it's burned through these new clean technologies. So that is a formidable obstacle, but not impossible, and it's not one we can afford to fail on, either.

Question: What might a region like New Mexico look like to our children in 2050? How might their lives be different?

Answer: 2050 is a long way out, and it depends very much on the action we take. But could I just give you a very local view that you might want to expand into that global view? In Australia, we have one large river system called the Murray-Darling river system, which this year is now in crisis, and it supplies water to a city of 1.1 million people called Adelaide. And we grow 40 percent of our projects on that river system. By the end of this summer [February in Australia], that system will be in collapse by the look of it. We face the very real possibility of having bottled-water distributions in Adelaide. That's the sort of crisis that you could easily imagine happening in your part of the world, where water is a key issue, because as our climate warms, rainfall is decreasing in dry areas and stream flow is decreasing even more than rainfall is. The really frightening thing is that we had average rain over the Murray-Darling basin this year, and it's still done nothing to avert this disaster.

Question: Explain how if you have average rainfall, climate change could cause a river system to collapse.

Answer: The heat from the atmosphere is transferred into the soils, giving us warmer soils, and water evaporates more readily from warm soils than cold soils. And plants are more stressed by the warmth, so they need to use more water. So if, for example, a certain amount of rain falls in that area, in the past a separate proportion of that might have contributed to stream flow. Today we have a 15 percent decline in rainfall on long-term average, which equates to a 70 percent decline in stream flow.

Question: You and other scientists said we have one to two decades to act to reduce emissions in order to avoid catastrophic change. You mentioned a littler earlier the new IPCC report. Does that change things?

Answer: Absolutely. You've picked up on the key issue. We used to think we had 10 years because the threshold to dangerous climate change looked like it was about 10 years away. That's because we weren't measuring what's called the carbon-dioxide equivalent accurately in our atmosphere. The new IPCC report does measure that accurately, and we now know that we're already over the threshold. So there is no more time. We must act now; the 10 years is up.

Question: You talk about dangerous thresholds. Tell us what those are.

Answer: No one can say exactly what part of Earth's climate system will be stabilized or where the big threats will come, and I must say I've learned my lesson in trying to project what they might be and getting it wrong. I didn't predict in Australia the urgency with which the water issue would become evident. So I don't know which of the stresses are going to be the important ones in the next decade. But what we've got to watch out for is stresses that do to the human species what we see in the natural world, which is change their resource availability to the point where they become endangered.

We live in a global civilization, and we are intimately connected one to the other around the world. So changes in Afghanistan, as we see, have big impacts in the U.S. instantaneously. We all live in this global society, so if the stress is sufficient to start causing the breakdown of global law and order and global trade, we will see very unfortunate consequences, I think.

Question: Climate scientists say we're committed to a certain amount of climate change through 2050 no matter what we do because of the amount of carbon that's in the atmosphere already and will remain there. But what if someone came up with the technology to take carbon out of the atmosphere or a geoengineering solution to cool the earth?

Answer: The short answer is nobody knows, because we don't yet know whether we've crossed that threshold for dangerous climate change. And that's the point where those positive feedbacks kick in to the point where the climate changes regardless. So let's just take a step back from that and look at the other question, which is really what is the amount of climate change we'll experience this century as a result of the greenhouse-gas burden already in the atmosphere. The standing stock of greenhouse-gas pollutant in the atmosphere is on the order of 200 gigatons that's built up since 1800, since the beginning of the Industrial Revolution. If you look at how you might draw down that standing stock of gas pollution, we've got several tools in the toolkit that can do that already without resorting to some high-tech response.

The first is the regrowing of tropical forests. It's entirely possible that 20 years from now we'll be regrowing enough forest worldwide to be pulling 10 gigatons of carbon out of the atmosphere per annum. Now that might be the upper bounds. But that is 5 percent of the standing stock of the pollutant that we could be drawing out of the atmosphere per annum were we to get carbon trading up and make this happen. ...

The second big area where we could do that is in agriculture. The development of the pyrolysis-based technologies, which involve the partial burning of crop waste, allow us to sequester by 20 years from now, even less, 10 gigatons of carbon or thereabouts in our agricultural soils every year. So between the tropical forests and agricultural initiatives we have the potential to be drawing down the standing stock of the pollution by
10 percent per annum in just 20 years' time. So once you develop those technologies to that scale you can see that the extent to which you're committed to dangerous climate change is perhaps not as great as we previously imagined.

Question: Do we have the technology to decarbonize by the time we need to?

Answer: Yes, we do, and the Californians are rapidly proving that, with multibillion-dollar investments now in concentrated P.V. (photovoltaic) technologies and in solar-thermal technologies to generate baseload electricity. That is a quantum leap. We're already there with that. We're there with wind. We are getting very close to being there with geothermal power. So I'm absolutely confident that we'll get there.