Dr Iain Stewart
Earth – The Climate Wars
Sunday 14 September on BBC TWO
Global warming, and how to combat it, has provoked intense debate, changed the way we see the planet and created headlines around the world. But when and how did scientists first discover global warming, why has it led to such furious debate and who should we believe?
In BBC Two's three-part series, Earth – The Climate Wars, geologist Dr Iain Stewart (Earth – The Power Of The Planet) presents a definitive guide to the history of climate change.
He tells Programme Information about the series.
What have you learnt
from this series about climate change?
Until a few years ago, I was a bit of a climate sceptic. Geologists are only too aware that the climate is always changing and that our planet has experienced very different conditions in the past – warmer, wetter, drier, and colder; far more carbon dioxide in the air; higher sea levels and the rest.
We geologists are used to these changes happening over non-human timescales – hundreds of thousands to millions of years – so it took me a while to latch on to the notion that it was the rate of change that was important. I was really gob-smacked when I saw the ice cores from Greenland and was able to put my finger on the point in the core when the planet switched out of an ice age and into a warm period over the course of a single season. At most, this fundamental change may occur over one to three years, but it's certainly not five or 10 and it's definitely not the centuries to hundreds that I learned about when I did my geology degree 20 years ago.
What is truly scary about climate change is not any of the specific scenarios of rising seas or melting ice, but the sense that our planet's climate exists on a knife-edge balance and we really don't understand what pushes us over the edge, which makes our great chemistry experiment with the world's oceans and atmosphere all the more short-sighted.
What was the best part
about making the programme?
Being able to go to where the action is – where the planet is virtually changing in front of our eyes. Sometimes they're places that I know quite well and even go to with my geology students at Plymouth, like the fossil waterfalls in eastern California which we visit on our Death Valley field trip as evidence of dramatic past climate warming.
But often they are new places that I've only read about in scientific papers or books. One of the great experiences was spending time among the remarkable settlements of Anasazi peoples in the American south west, an advanced society that magnificently managed the challenges of a precarious water supply during warm medieval climatic conditions but ultimately were finished off by a series of mega-droughts about 700 years ago.
I'd been brought up with Ansell Adams's stunning black and white photographs of their deserted remains, precariously hanging from great sandstone cliff faces, so it was wonderful to finally climb up to see them. Being a geologist helped me appreciate one aspect of their remarkable existence – their deep understanding of the water cycle and the importance of springs and other parts of the geological plumbing system – but to get the full picture you really need to talk to people with other perspectives. And that's the other great part of making a programme like this – speaking to other experts about their fields. For the story of the Anasazi it was a chance to hear from archaeologists and anthropologists about the controversy that surrounds their end, which includes violent inter-settlement struggles and even cannibalism.
Of all the pioneers
in the history of climate change science who impressed you the most?
One of the great characters of climate science over the last four decades has undoubtedly been Dave Keeling, the exceptionally dedicated scientist who has given us the carbon dioxide record from Hawaii (among other places), arguably the one piece of uncontested evidence in the whole global warming debate.
If the global warming camp has a hero, then it's probably Keeling, whose dogged determination to measure carbon dioxide in the atmosphere – a rather unfashionable preoccupation in the Sixties – has revolutionised the subject.
The most remarkable thing about Keeling was his attention to detail. He was a compulsive recorder of the minutiae of everyday events, logging all his telephone calls, even keeping a rota of his garden watering. Unfortunately, Dave died a few years ago but his son, Ralph, is following in his dad's footsteps, and is now a leading atmospheric chemist in his own right. It was great to spend time with Ralph, seeing how his father overcame the technical difficulties of precisely measuring carbon dioxide and also the political difficulties of keeping a very 'un-sexy' line of research going in the face of ever present funding cuts.
Today, atmospheric science and the climatic effects of carbon dioxide studies are major areas of funding but still, on the sidelines, there are modern equivalents of Keeling working away on their pet project. And that's the beauty of science, I guess.
What do you think will
happen in your lifetime with regards to climate change?
That's the tricky one, largely because it depends on what we – society – do. Many climate scientists are seriously worried that we'll permanently lose the summer Arctic sea ice, meaning that for the first time since we explored the world's oceans, humans will be able to sail over the North Pole in summer without encountering ice.
It may not seem a big deal to us, but for the Arctic communities this will mean a huge change in lifestyle. It's unlikely that in my lifetime the year-round Arctic ice will disappear, or that we'll lose the ice from Greenland; those will probably be left for my children's children to experience.
As for other effects, there's no certainty but it is easy to see how the American south west could collapse. The thirsty mega-cities like Las Vegas and Phoenix are making evermore unsustainable demands on the meagre water supplies, and with the region in its eighth year of drought, the tensions are becoming palpable. Geologists are only too aware that this region has been wracked by debilitating droughts that spanned many years to a few decades in the past – we've just not seen them in modern history. That's the beauty of geology – it gives you that long-term perspective.
What can we do at home
to help stop climate change – do you have any tips for small
changes we can make that might make a big difference?
I still have a long way to go before being viewed as some kind of role model for reducing our climate footprint. I fly too much and beyond the normal recycling and energy-saving measures (the loft is well insulated) that many people are now doing, I've no amazing personal recipe to impart.
If society is to make any progress on effectively dealing with climate change at a regional or global level, what is imperative is that ordinary people help build a political climate at grass-roots level that accepts the problem exists and demands some serious actions by business and government. For me, that begins with people accepting that there is no hiding place left in the science – the overwhelming consensus of the vast body of scientists that study climate is that the trends we are seeing in the air, the oceans and in our ecosystems are entirely consistent with the theory of global warming, while the alternatives offered by sceptical scientists – even the much heralded role of the Sun – so far fail that test.
Blaming scientific uncertainty is now not an option to delay action. Sure, actions by individuals can make a difference, but real progress will only come when individuals come together with a strong, common voice to demand that rhetoric turns into regulation. And that's where I see my role – in convincing ordinary folk that this is an issue that they should care about, not because it will affect them but, more insidiously, it will be their legacy to their kids and grandkids.