There are fewer wildfires globally now than 20 years ago. In fact, the incidence of fire has declined by 15 percent over the past two decades, so there is nothing to worry about. Fact: It’s true that there are fewer wildfires today than 20 years ago, but this figure is misleading. Two thirds of all such fires are in Africa, and these have declined over the past two decades. But this is not because climate change is benign, but because of increased farming, which has reduced the areas where fires take place. It is also because the changing climate has increased precipitation in tropical Africa, thereby reducing the incidence of fire. By contrast, in the temperate and boreal forests of Europe, Australia and North America, fires have become more frequent and more intense. 

There are fewer hurricanes today than there were decades ago, so they do not present any threat.  Fact: There is some truth to this statement, as hotter temperatures are increasing wind shear, which can break up hurricanes before they reach land. However, hotter temperatures are also increasing evaporation, which puts more latent heat (i.e. energy) into the upper atmosphere. This has made hurricanes more powerful and destructive. So, there are fewer hurricanes today, but they are more damaging. Overall, this is a bad outcome.

Deaths from climate-related natural disasters like fires, droughts, storms and floods have dropped by 98 percent over the past century, mainly because of improved warning systems and better evacuation plans. This means it would be far better to adapt to climate change than to try to stop it.  Fact: It’s true that deaths from natural disasters have fallen by 98 percent over the past century, due to improvements in technology. But those improvements were made at a time when the Earth’s climate was stable. This will not be the case in the future, as global warming starts to disrupt the Jet Stream, the Gulf Stream, deep ocean circulation and other key elements of the climate system. And even if we can limit human casualties through improved warning systems and better evacuation plans, we cannot do the same for the animal world. In the end, we are dependent on a properly functioning ecosystem, and this will not be the case if temperatures continue to rise. It’s also worth remembering that all of human history has been based on a stable climate. To believe that new technology can compensate for ending this is to gamble with our future. 

Over the past 50 years, polar bear numbers have increased from 5,000 to 30,000, so they are not under threat from global warming.  Fact: Polar bear numbers have indeed increased, but only because hunting was banned in the 1960s and 70s. However, about 70 percent of Arctic sea ice has disappeared over the past 35 years, threatening the bears’ habitat. In some regions the bears are still doing well, but in others they are under threat. If global warming continues, they will largely be extinct in the wild by 2100.

Species can adapt to climate change. They survived the various ice ages we’ve had in the past, so they’ll survive the current warming. Fact: Yes, species can and do adapt, but not quickly. When the ice ages hit and receded, species had thousands of years to adapt and/or move. This time they will only have decades or, at best, a few centuries, which will not be enough time. They will also be unable to move, as agriculture now occupies 46 percent of the Earth’s habitable land.  There have been five mass extinctions in the past, with each resulting in the loss of over 75 percent of all species. Scientists believe that four of these events were triggered by climate change, mostly resulting from volcanic activity, which first froze the planet (due to increased albedo from additional particulate matter) then heated it (due to increased CO2). [The other mass extinction, 65 million years ago, was triggered by an asteroid striking the Earth. It resulted in the passing of the dinosaurs.] Some scientists believe we are headed for a sixth mass extinction, as a consequence of global warming. They suggest that we could lose up to 40 percent of all species by the end of the century if we cannot get our greenhouse gas emissions under control. If such an extinction occurs, it will take millions of years for the planet to recover.

We’ve had higher levels of CO2 in the past, and life has survived quite successfully. So, there is no need to worry now.  Fact: It’s true that CO2 levels were much higher hundreds of millions of years ago, but the amount of solar energy reaching the Earth back then was also significantly less (possibly only 70 percent of what it is now). This is because stars like our sun get hotter as they age and emit more radiation. Another reason is because at that time the continents were joined together near the equator and were reflecting more solar energy back into space. These two factors cancelled out much of the impact of the CO2 level. If CO2 were to return to the level of the distant past, the result would be catastrophic, as so much more solar energy is reaching the planet now. It should also be noted that the last time CO2 levels were as high as they are now (427 parts per million) was during the Pliocene period, around about 3 million years ago. At that time, sea levels were 10 metres higher than now, humans had not yet evolved and we certainly didn’t need to feed 8 billion people.

As the planet heats up, there will be an increase in water vapour. This, in turn, will cause more clouds to form, and these will reflect away more of the sun’s rays, thereby reducing some of the heating effect of CO2 emissions. In other words, clouds will act as automatic stabilisers, saving us from the worst impacts of global warming. There is therefore nothing to worry about. Fact: This argument was put forward by two of the world’s leading climate sceptics, Professor Richard Lindzen and Professor Roy Spencer, in 2011.  The science of cloud formation is complex and not well understood. Low level clouds (like cumulus) do increase albedo (reflection) and therefore have a cooling effect on the planet. High-level clouds (like cirrus) absorb heat (given that they are composed of water vapour) and consequently warm the planet. In a hotter world, the overall impact will depend on which type of clouds form. The current view is that more cirrus clouds will form than cumulus ones, meaning the warming impact will be slightly greater than the cooling effect. But even if that were not true, and only low-level clouds were formed, this would have a marginal impact on the climate.  But even without a full scientific investigation, the flaw in Lindzen’s and Spencer’s argument should be obvious. If clouds really did negate the effects of temperature changes, how could we have had temperature changes in the past? In other words, how could the Little Ice Age or the Medieval Warm Period have occurred – let alone actual ice ages and thaws? Surely changes in cloud cover would have prevented these changes from happening. So, clouds are not our saviours. Finally, it should be noted that Spencer and Lindzen are not just sceptics when it comes to climate change. Spencer also rejects the theory of evolution, while Lindzen rejects the notion that second-hand cigarette smoke is dangerous to health. Both are mavericks in the scientific community.

Warmer temperatures will lead to more evaporation and therefore more rain, so global warming will not lead to a drier planet. Fact: Warmer temperatures will indeed lead to more evaporation. In fact, for every 1°C of warming, there is a 7 percent increase in water vapour, meaning more of the planet’s finite supply of fresh water winds up being trapped in the atmosphere. Even if rainfall increases, the Earth will still be drier. An analogy might be a bath which, instead of letting water drain away, pumps it straight back into the bath. The system is primed so that the amount of water leaving via the drain is exactly matched by the amount being put back in via the tap. This closed system is in equilibrium – like the Earth’s hydrological system at any point in time. Now, if we elongate the pipe, allowing it to hold more water, the amount in the bath goes down. If we also speed up the rate at which the pump pulls water from the bath and spits it back out of the tap, the system moves to a new equilibrium. This time, however, more water is being pumped into the bath (i.e. more rain) but less is actually in it (i.e. a drier Earth). 

CO2 is good for plants, so increased levels of CO2 will ‘green the planet’ and increase agricultural production.  Fact: The plants we should be looking at are crops, not greenery in general. These do grow better with more CO2, but they do not do well in higher temperatures, and you can’t have more CO2 without more warming. Wheat is particularly susceptible to heat. [Climate sceptics often counter this by claiming that the rise in CO2 is not being accompanied by hotter temperatures, but this requires them to deny that global warming is real – something most of them know isn’t true. So they cannot use this line of argument as a way of justifying inaction in the face of climate change.] Recent scientific research has shown that as CO2 levels increase, the nutritional content of crops decreases, due to a reduction in vital trace elements like zinc and iron. The incidence of crop diseases like wheat leaf rust and corn rust is also greater, as is the prevalence of weeds. In addition, some pests (like the Colorado potato beetle and the European grapevine moth) also thrive in higher temperatures.

The biggest killer in the world is cold, not heat, so it’s a good thing that the Earth is heating up.  Fact: It’s true that cold kills more people each year than heat, but that is not an argument against climate action, as global warming is a threat to the biosphere, not individuals. It will affect people by impacting food supplies and ecosystems. In addition, most people who die of cold do so because they are living on the streets or are too poor to pay for heating. You don’t solve this problem by heating up the world. You solve it by raising people’s incomes and living conditions. [Interestingly, many of the same people who claim that cold is a bigger threat than heat are indifferent to the suffering of those who cannot afford proper heating.] High temperatures and high humidity are a deadly combination. Medical investigations have revealed that large areas of the tropics will become uninhabitable if these warm, humid areas increase in temperature by just a few degrees.