We can cool the planet by seeding the oceans with iron dust, to generate phytoplankton blooms. These would absorb the CO2 we are currently emitting. Fact: This idea, known as ‘ocean iron fertilisation’, works in principle, in that phytoplankton do require iron in order to grow, and seeding the oceans does produce phytoplankton blooms. Unfortunately, studies have shown that most of the CO2 absorbed by the blooms is released back into the atmosphere when the phytoplankton die, rather than sinking to the bottom of the ocean, as proponents of the idea had hoped. This means ‘ocean iron fertilisation’ is not a viable solution to the problem of global warming. Not surprisingly, its advocates have gone quiet of late.

If we need to, we can put gigantic reflectors into space, to stop some of the sun’s rays from reaching us. This will cool the planet. Fact:  This idea is another example of ‘solar geoengineering’. It has the advantage of being less dangerous than putting sulfate aerosols into the stratosphere. However, it would be prohibitively expensive, as it can cost up to US$400 million to put a large satellite into space. No one knows how many of these reflectors would be needed to cool the atmosphere. Whatever the cost, it would be much cheaper to simply stop emitting greenhouse gases.

We can counter the warming impact of greenhouse gas emissions by firing particulate matter into the stratosphere, to reflect some of the sun’s rays back into space. Fact: This idea, known as ‘solar geoengineering’, seeks to emulate the impact of large volcanic eruptions like that of Mount Pinatubo in 1991, which cooled the atmosphere by 0.6°C for about 15 months. The scheme has the advantage of being cheap and feasible, but the disadvantage of being potentially very dangerous.  Unfortunately, putting sulfate aerosols into the stratosphere will not precisely offset our CO2 emissions, as the two processes impact the Earth in different ways. The former blocks the entry of heat, while the latter blocks its escape. This means that while the Earth’s temperature would indeed cool if we bombarded the stratosphere with aerosols, that cooling would not be spread evenly across the globe. It is entirely possible that the polar regions would become hotter rather than cooler, and that the polar ice caps would melt at a faster rate rather than a slower one. This, in turn, would reduce the level of albedo on the planet, increasing solar radiation rather than reducing it. The simple fact is, we don’t know what the overall effect would be if we started experimenting with the planet this way.  Another problem is that eventually all of the particulate matter sent into the stratosphere would return to Earth, creating acid rain. This problem was deemed so severe in the 1970s that laws were passed to stop industries from polluting this way. Acid rain is dangerous to lakes, rivers and people’s health. It is also damaging to the ozone layer.   Then there is the problem of politics. Who decides how much particulate matter is put into the stratosphere, and what happens if a rogue state decides to ‘go it alone’? It is difficult to get agreement among nations on any issue, let alone one as important and difficult as this. Finally, there is the question of what to do if we make a mistake. If, for example, we were to put too much particulate matter into the stratosphere, there is simply no way to get it down until it descends of its own accord – and we don’t know how long that would take. In the meantime, the impact on the climate could be catastrophic.

If global warming gets out of hand, we can use carbon dioxide ‘fans’ to suck CO2 out of the atmosphere and sequester it safely underground.  Fact: Certainly, this can be done, but it is prohibitively expensive. Given the technology available today, it costs about US$100 a tonne to scrub CO2 from the atmosphere. This means that in order to remove all the CO2 emitted by humans in a year, we would need to spend US$5.5 trillion, or more than Japan’s entire GDP. It would be much cheaper to simply stop the emissions in the first place.  

The land mass of some islands has increased over the past six decades, not decreased, so talk about islands being inundated by sea level rise is rubbish.  Fact: The land mass of some atolls has indeed increased over the past half century, but this is not evidence that climate change poses no threat. Tuvalu, for example, has seen an increase in its land mass of 2.9 percent over the past few decades. The reason is that waves, storms and tides push sand, gravel and coral debris onto the islands’ shores. That’s how the islands were formed in the first place. However, while they might be growing out, they are not growing up, meaning they are still negatively impacted by sea level rise, just like non-coral islands like Fiji. And with sea levels expected to rise by a metre this century if we don’t cut our carbon emissions, sediment-based land expansion will be overwhelmed and coral atolls will indeed start to disappear. 

3 million years ago, sea levels were 10 metres higher than they are today, yet CO2 levels were roughly the same as now. So, why aren’t sea levels 10 metres higher in the 21st century? This is proof that they are unrelated to CO2.  Fact: Sea levels have a long lag time following temperature increases. It may take hundreds of years before they reach their peak, but the evidence suggests that this is the direction they are headed. At current rates of temperature increase, scientists expect a rise of up to one metre by the end of the century, with more coming after that. 

In the 1930s, the United States experienced a series of heatwaves that were much more severe than anything experienced today. Hence, the notion that climate change is making things worse is simply wrong.  Fact: Once again, this myth contains an element of truth. The worst heat waves the United States has experienced were in 1930, 1931, 1934 and 1936, but there were specific reasons why these were so bad. This was the era of the ‘dust bowl’, when extreme drought, exacerbated by poor land management, resulted in an environmental disaster in America’s west. Outside of those four years, the frequency and extent of heatwaves in the US over the last two decades is greater than at any other time since 1895.

Australia has had bushfires in the past that were far worse than the ones today. The 1974-75 fires burnt 117,000,000 hectares, which is six times as much as the fires of 2019-20.  Fact: The fires of 1974-75 were mostly of grassland in the Northern Territory and Queensland. The authorities didn’t even know they had occurred till after the fact. The 2019-20 fires were in forested areas and were four times more damaging than the previous worst such conflagration.

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.