Welcome to the second piece of my two-part series on the State of the Environment chat with Professor William (Bill) Laurance from James Cook University. Last week in Part 1 we discussed Biodiversity and why it is so important.

This is another meaty article but one that is so important given that climate change is really changing life as we know it. It’s important that we get this knowledge out of our Universities and science institutions and into the general community so that we can all know as much as possible about the topic, and feel empowered to do something to address it.

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What is climate change and what impact is it having on life as we know it?

The climate change we talk about it is human-caused climate change or anthropogenic climate change, and it is the idea that humans are increasingly spewing so much pollution into the environment and atmosphere that it is changing the climate.

There’s no question that the chemistry of the atmosphere is changing. We know that if we go back to the pre-industrial era, there was about 280 parts per million of carbon dioxide in the atmosphere. Today there is more than 400 parts per million. It’s basic physics to say that if you put more carbon dioxide (which is a heat-trapping gas) into the atmosphere, than it will be warmer. There are other greenhouse gases such as methane and nitrous oxide etc. that we are producing a lot more now. These are also heat-trapping gases that contribute to warming.

One of the places where scientists have sometimes gotten themselves into trouble is when we’ve not been as upfront about uncertainties as we should be. One of the things that I like to do is distinguish among different kinds of uncertainties. I refer to Donald Rumsfeld who tried to distinguish among three different kinds of unknowns and although the press ridiculed him about this, I think he had a good point. Rumsfeld talked about things that we know, known unknowns, and unknown unknowns. Scientists have been criticised because we haven’t always been explicit about what we think we know and what we don’t know we don’t know. I’ve managed to dodge most of the bullets so far by emphasising that there are plenty of scary things going on but we need to be clear about the things that we know, the things that we think we know, the things that we know we don’t know, and that things that we don’t know we don’t know!

So, we know that the atmosphere is changing and that it’s getting warmer. We know that from the beginning of this century, 15 of the 16 years have been the hottest years ever recorded. We know that we’re moving into really hot territory and we would have to go back millions of years to find carbon dioxide levels that are as high as what we are seeing now.

There is a huge amount of natural temperature variation so what we see is human-caused warming interacting with a substantial level of natural variation. This variation is associated with the El Nino – Southern Oscillation, the Indian Ocean Dipole, Milankovitch cycles, and sun spots etc. We know that there are a whole lot of things that cause natural variation.

We know that even without human-caused influences we are going to have some years that are really hot, have droughts, and high-rainfall events. But what we’re doing is adding on top of that, human-caused climate drivers. Mostly these are pushing things towards warmer conditions. For instance, our heatwaves are becoming more frequent and intense.

As a biologist, I can tell you that it’s not so much the steadily rising thermometer that has us worried, it’s those occasional heat waves that scare us. For wildlife, even a difference of a degree or half a degree can be critical. For instance in Australia, once the thermometer hits 41°C, flying foxes start dying in their thousands. We can see the evidence of this happening plus massive bleaching events in the Great Barrier Reef, lizard populations in large parts of the world are vanishing, migratory birds are changing their paths, and plants are changing the timing of their flower production. These are the things that we know are happening.

What we don’t know is how much higher the greenhouse gas concentrations are going to get, we don’t know how much hotter it’s going to get. When we start talking about what the biological consequences are going to be, there are still many different things that we don’t know.

We have a lot of suspicions, for instance we think that the tropic species may be most vulnerable to global warming which surprises people. This is because they live in an area which has little temperature variation, in fact most of the temperature variability has to do with the elevation of where they live. Species in the tropics are adapted to very stable temperatures and they tend to become thermally specialised i.e. are adaptive to only a narrow range of temperatures. We know that there is a huge number of endemic (locally specialised species) that live on tropical mountains. There’s no gene flow with anything else because they’re isolated, and so they evolve into unique forms which are specialised for that particular place. So, you’ve got this thing that’s adapted and specialised as a thermal specialist; it’s adapted for wet, cloudy, cool conditions, what happens when the temperature goes up? Everything we know tells us that their geographical ranges will shrink and their populations will fragment, and eventually they’re not going to have anywhere to go. That’s why we think that the places where we’ll see the biggest impacts on biodiversity may in fact be in some of the warmer places in the world, particularly tropical mountains, where there are enormous amounts of species.

Those are some of the things that we think we know. We’re speculating but we’re reasonably confident that we could lose a lot of biodiversity on some of these tropical mountains which are these amazing hotspots of biological diversity around the world, as well as other ecosystems where species are adapted to cooler conditions.

Then you start getting into things that we know that we don’t know and there’s lots and lots of those. For instance, one of the things that we know we don’t know is how the rising levels of carbon dioxide in the atmosphere affect forests. There are two camps of scientists here; they don’t like or talk to each other very much and they violently disagree.

One camp thinks that because we’re getting more carbon dioxide in the atmosphere and plants use this for photosynthesis, this would fertilize the plants and they will grow faster. So, we should see forests becoming more massive and plants growing faster in different parts of the world. In fact, this argument is that the natural ecosystems should be absorbing some of this excess carbon dioxide that we’re spewing into the environment and in fact helping us to save ourselves. We’ve done work in the Amazon for years on this and we in fact do see that many of the forests there seem to be growing faster. We’ve estimated that the intact forest of the Amazon could be absorbing as much as half of a billion tonnes of carbon dioxide per year. That’s quite a bit considering that we’re currently putting about 8 billion tonnes of carbon dioxide into the atmosphere.

The different point of view, if you look at a plant you can think of it being like a lizard or frog and effectively it’s like a cold-blooded animal. When the temperature goes up, cold-blooded animals’ metabolic rate goes up. The argument is that when it gets warmer, instead of growing massive, plants are going to have to burn more energy for their basic metabolism. If they burn more energy just to stay alive, that means that they have less energy for growth and instead of growing faster as it gets hotter, they’re going to grow slower. Instead of getting massive forests, we’ll see forests growing more slowly and shrinking over time.

This is a scarier scenario because you are getting this positive feedback. Whenever you hear the phrase ‘positive feedback’ in science, it should be a danger signal. That’s like a snowball coming down a hill and getting bigger and turning into an avalanche. The idea being, as it gets warmer, plants burn more energy, and give off more carbon dioxide because they’re consuming more carbon dioxide to stay alive. That contributes more carbon dioxide to the atmosphere, which means it gets hotter, as it gets hotter, the plants give off more carbon dioxide. That’s the more frightening scenario.

We don’t know which one of those realities is true right now. There are lots of these known unknowns, but this is one of the big ones.

Then we get these unknown unknowns and these are the things that come flying out of the blue and smack us down in the back of the head! When you get a strong El Nino event which happens every seven years or so, the dogma is you get droughts in the Amazon but they only happen in certain places. They happen in the Southern and Eastern Amazon mainly but these are already the driest parts of the Amazon anyway. In 2005 we saw something that nobody had never seen before. It was a completely different kind of drought, there were no El Ninos during this time so it wasn’t driven by that, it was driven by very high Atlantic sea surface temperatures. These temperatures apparently resulted from a combination of natural climatic variability and human-caused global warming lining up together. These atypically high Atlantic sea surface temperatures spawned Hurricane Katrina which of course had the devastating effect on New Orleans.  In addition to that it took the Intertropical Convergence Zone and drove the rain-bearing low-pressure system northward. So, what we saw was a drought that not only effected the Southern and Eastern parts but the entire Amazon base. Everybody thought it was a once in a lifetime event because no-one had seen it before.

The effects of this drought were devastating because they hit parts of the Amazon that were not accustomed to droughts. The plants in the Central, Western and Northern areas were not adapted for droughts and tens of millions of trees were killed. There were billions of tonnes of atmospheric carbon emissions produced by the death of all of these trees.

We never thought we would see it happen again in our lifetime…..in 2010 it happened again and it was even worse. So now we’re scratching our heads – not knowing what is going on. Is the Amazon entering a new climate dynamic? Is this something that has been the result of human-caused global warming? Are we now entering completely new climatic territory? That’s where we are – this is an unknown unknown. Nobody expected this to happen and yet we’ve now seen it twice in five years. If it happens another time I think that everybody will agree that we are entering a completely new world.

The frightening thing is that it is not just these droughts that are happening, but the Amazon is also being opened up like a flayed fish by new roads, forest destruction, habitat fragmentation, and logging. We know that these fragments of forests and these log forests are much more vulnerable to fires and destructive activities because the forest canopy that traps the moisture and keeps the forest dark, humid, and moist is being ripped out. The new roads make it much easier for ranchers, slashers, and loggers to come in and light fires. Once you add in these unprecedented new droughts that are spreading across the Amazon, the bottom line is that we may be entering a dangerous new world.

When we try to predict future climates, we get teams of really smart people and we give them powerful computers and they make complicated computer models called Global Circulation Models (GCMs). NASA has their own GCM, the British Meteorological Society has their own GCM, Australia’s CSIRO has its own GCM. The frightening thing is when we run the different GCMs under different future scenarios, even though we run them under the exact same conditions, we keep getting different answers. There are dozens of these different GCMs and where it gets really scary is they tell us wildly different things about rainfall or precipitation.

The decision makers i.e. politicians want to know what’s going to happen in their area in the future. They need to know for agricultural reasons, water supplies, energy supplies, and for nature. Water is incredibly important. I say if you want to predict the future rainfall or precipitation for any part of the world, go down to your local casino, go to the craps table, get yourself some dice, throw them out onto the table and you’re going to have about as much chance as predicting the likelihood of rainfall in a specific area as you will with some of our smartest people using our most powerful computers. That to me is scary.

I don’t think we need to tell politicians that we know exactly what the future is going to hold. I think we need to tell them that we are playing Russian roulette with the future of the planet and that the best tools we have, tell us that there’s enormous uncertainty. I think we can acknowledge all this uncertainty and still have incredibly powerful arguments about what the future is going to hold. There are lots of things that we don’t know. We can use the best available information and make the best guesses, but the bottom line is that any climate scientist that tells you they know exactly what is going to happen, is not being forthright and honest.

We know that the signs we are seeing right now suggest that things are changing in ways that could be earth-changing, world-changing, and economy-changing. This can have major impacts on human welfare as well as ecosystems, but beyond that we must acknowledge very readily that there are still many uncertainties out there. The scariest thing about climate change is not what we know but the things that we don’t know.

What changes can we expect to see in the next 10 and 50 years?

If you look at the different kinds of computer simulations, one thing that seems robust across all different future scenarios is that we’re looking towards a future of more extremes. Particularly more heat waves, probably more droughts in certain scenarios, and more extreme rainfall events.

These models that are run at a global scale. What we would like to know that they don’t tell us, is where and when to expect these things. We can’t predict when the next killer heatwave will hit Europe.

Beyond that, we’re pretty sure that things are going to get warmer. It’s likely in many parts of the world that we’re going to have warmer winters. In certain places in the world, western North America for instance, the snowpack is incredibly important for regional water supplies because they don’t have enough storage capacity in their hydroelectric dams in order to provide their water and energy needs.  They rely on the snow gradually melting throughout the spring and the summer, and progressively filling up the reservoirs as they’re drained off to generate power, irrigate, and supply cities. The scenarios now suggest that we will get snow melting off more rapidly, it’s not going to be aligning with when they are needing their water supplies to be produced. That’s probably going to have a major impact on everything from agriculture to energy generation to fires to natural eco systems. There are lots of other different parts of the world where that kind of dynamic could play out.

In terms of rainfall, it’s very difficult to make predictions. If you look at these ensemble models where they take all the different GCMs and lay them on top of each other and take the average, you do find that there are some parts of the world where there seems to be more agreement than others. But the bottom line is we just don’t know.

There’s an old Dutch saying “making predictions is difficult, especially about the future”. I think that there’s a real level of truth to that. Unfortunately, we are changing Earth in so many different ways simultaneously and we are struggling in trying to say what the future will be. The computer models that we work with are really simplified versions of reality and we’re right at the margins of what we are able to do. We can make broad guesses about the trends that are happening and many of these are alarming. But I believe what we don’t know is more frightening than what we do know.

What needs to happen to halt or slow the current rates of climate change. Is it too late to reverse it?

Yes, it is too late to reverse it. Even the greenhouse gases we have in the atmosphere now have residence times of many decades to centuries. We have a lot of climatic momentum, we’re not going to stop global warming even if we stopped emitting gases right now.

One of the best things that we can do is stop deforestation to the degree that we possibly can. We need to foster forest regeneration especially in the tropics and sub-tropics, that’s where things grow fastest and year-round.

We should try to move as fast as we can to ‘decarbonize’. Coal-fired generating plants are the worst things that we could be creating right now. I know that Australia has a huge economic investment in coal, and the notion of ‘clean coal’ is a ridiculous statement. The realities of carbon capture technologies are that they are incredibly expensive and not cost effective. The alternatives are things like natural gas as a natural bridging technology and is certainly much less polluting than coal.

Hydro has both its advantages and disadvantages. Solar, wind, and biomass technologies can certainly help as a mix of alternative energies but they have some complications. For example there are technical issues around meeting baseload capacities.

The bottom line is that there are solutions and we have seen the more conservative governments in Australia combatting the increasing investment in alternative energies such as solar and wind. This is ridiculous in a country such as Australia where you have such high solar radiance and the capacity for solar alone is incredible. A lot of these corporations and their lobbyists have invested heavily in their infrastructure, transmission capacity, and in their plants. They want to recapture their investments so they’re actively trying to combat solar and wind.

There is a lot of capacity to reduce emissions including opportunities from the Paris and Morocco Climate Accords, and we must keep momentum going there. These are all the things we can do that will help us out of the danger areas the fastest, in terms of trying to find shorter term solutions i.e. in the order of decades.

Are there actions that the average person can do to address climate change?

There are lots of things we can do including turning off air conditioners.  Painting your roof with heat reflective paints can make a ridiculously big difference in the amount of energy that you need to use for cooling etc.

Turn off your light switches. Much of the power in Australia comes from coal-fired generating plants. Every light switch, air conditioner, and fan we turn off makes a big difference. It all adds up and I think that we can move towards better technologies and make smarter decisions.

Australia on a per capita basis burns just about as much energy and creates just about as much greenhouse gases as almost anybody on the world. It’s higher than the U.S and Canada. There’s only a few countries in the Middle East that have higher per capita carbon emissions than Aussies do. The U.S, Canada, and Australia are relatively similar in producing a lot of greenhouse gases per head so there are many prospects for these nations to be improving their emissions and providing a good example for the rest of the world.

What would you say to people who may be feeling that the problem is just too big?

A person who is engaged and active at some level can have an impact of many thousands of people. Most people don’t do anything at all. But simply if we can get people to be smarter about their energy use, that makes a big difference.

Avoid long commutes where you can and use mass transportation. Park your car and go inside instead of letting your vehicle idle in the drive-through at McDonalds. There is a great deal that we can do as individuals and these things do add up. It’s putting money in our pockets too.

There are many smart decisions we can make, it’s not hopeless. We are looking at serious issues ahead but the notion that we are victims and not able to do anything about it, is precisely the wrong idea.  We can have a voice, we need to have a voice. I encourage anybody who is interested to get engaged, join your local conservation group or become part of an organisation.

There are prospects for communicating with younger audiences. If you don’t get to talk to children until they are 12-years-old, they tend to be solidified in terms of their world views. I go around to 4th grade classes in my part of the world and talk to them about environmental issues because I find they’re very receptive at that age.

Are you optimistic about the future for our planet?

I think that my nature is to be optimistic, if I didn’t think there was hope, I wouldn’t be in this business. But I do think that things will get worse before they get better. We have a lot of tough problems ahead and we’re in new terrain in terms of our population, consumption, climate, and the impacts on nature. It’s clear that there’s never been a species that has done to the Earth what we have done. We have had global catastrophes that have done it but never a species.

If we don’t do anything, I think we would be looking at a much darker future than if we do something. We have to keep fighting the good fight, doing everything we can to try and make the world a better place, and try to help other people see that we can do these things too. We can’t sit around and do nothing, I think that would be a formula for profound damage and disappointment. It’s not the kind of legacy that we want to leave for our children, our grandchildren, and our great-grandchildren. We want to leave them with a planet that is at least as good as the one that we are living on right now. We need to take action now in order to make the world a better place.


About Professor Bill Laurance:

He is a distinguished research professor and Australian Laureate at James Cook University in Cairns, Australia. A tropical conservation biologist, he has written eight books and over 450 scientific and popular articles. He is a fellow of the Australian Academy of Sciences and has received many professional honors, including the Heineken Environment Prize. He is director of the Centre for Tropical Environmental and Sustainability Science at James Cook University, and founded and directs ALERT—the Alliance of Leading Environmental Researchers & Thinkers—a global conservation-advocacy group that reaches over 250,000 readers each week. He is also a four-time winner of Australia’s Best Science Writing Prize.