Taken individually, climate change and the threat of nuclear war each hold the potential to change the face of the earth and life on earth as we know it. A new book by earth and paleoclimate scientist Dr Andrew Glikson
of the ANU School of Archaeology and Anthropology
projects a scenario in which both have taken their toll.
Your book forecasts a very chilling future for our earth and all its inhabitants. Can you talk briefly about what you see in our future?
Climate scientists and other scientists talk about trends and possibilities rather than predictions. We cannot predict any particular type of event with accuracy with regard to its time and magnitude of because there is a lot of variability in nature. What we can project are the trends once they are confident. The probability is now that the globe will be warming further.
In the present it doesn’t appear that human civilization is doing anything effective to draw carbon dioxide down, which would be the most effective way to reduce warming. Currently the world maintains and expands a nuclear arsenal of some 16,000 bombs and missiles, many of which are on trigger alert. The probability that something might happen by accident or design is very high. So from both perspectives, the climate and the nuclear, we’re living in scary times.
I’m not trying to forecast but to elaborate on the factors that underlie the decisions by the Bulletin of the Atomic Scientists to set the Doomsday Clock to two and a half minutes to midnight, and that’s what the book is about.
You say in your book that the biosphere has already entered early to advanced stages of mass species extinction?
Mass extinction is going on right now and has been for a least a couple of centuries. The rate at which living species are disappearing is 1,000 to 10,000 times the background rate which existed earlier on 100 to 1,000 years ago.
One scenario hard to avoid is global warming to 3, 4 or 5 degrees Celsius above pre-industrial temperatures. It’s happening at the extreme rate to which most species will not be able to adapt. The world has had high temperature climates before, but most of the changes took place at a rate to which species could adapt. What’s happening now, it’s almost like an impact by an asteroid.
With nuclear war, the consequences depend on how many warheads explode and where they explode.
You came up with the term Plutocene to describe our present scenario. What is the Plutocene?
I am by training a geologist and we define periods of the earth based on fossils or changes in composition of sediments and chemical and isotopic traces. The Plutocene started with atomic testing in New Mexico in 1945. From that time, with further tests in many areas in the Marshall Islands, the Gobi Desert and other places, which shed plutonium which subsequently accumulated in a layer of sediment at the bottom of the ocean. This is a marker which began an era I named the Plutocene.
What are the characteristics of the Plutocene?
It’s a period dominated by a tropical climate and high radioactivity lasting for approximately 20,000 years, as controlled by the half-life of plutonium and the longevity of carbon dioxide in the atmosphere. During the Plutocene the earth will have tropical climate, sea levels will be higher, with not much ice at poles.
I’m not a biologist, but looking at the flora and fauna which would survive a nuclear exchange and high temperatures, you have to look at the arthropods. They have the highest resistance to radiation and tolerance of high temperatures. Then there are animals that live underground; they will fare better. Plants can take a fair amount of radioactivity. But under high temperatures, some plants will do better than others.
You mentioned the rate of rising temperatures earlier. When there might be the deployment of nuclear weapons is an uncertainty. But when are you suggesting this scenario might come about?
We don’t have a crystal ball to tell the timing of events. But we’re looking at events that happened in recent past and inferring consequences for the next century and millennia.
Is there anything we can do to prevent this from happening or is it inevitable?
The probabilities of a nuclear exchange are high. But if people come back to their senses and there is enough popular pressure to dismantle these suicidal machines in many countries, there is hope. There are calls, including a proposed disarmament treaty by the UN, which Australia declined to sign. If this happens, the nuclear threat declines.
With regard to the climate, it’s more difficult to draw down carbon dioxide on the required scale as it would cost hundreds of billions of dollars. We still don’t know whether this is possible. There are ideas such as using seaweed plantations, biochar farms, reforestation and so on. Should this be done on the right scale, maybe the rise of carbon dioxide can be arrested.