Category: Climate change

Today, 9th September 2021, BBC news includes a report which claims that most remaining fossil fuels – 90% of coal, 60% of oil and gas – must stay in the ground, “scientists say”. The UCL study is reported in Nature.

“Scientists say” suggests that scientists all agree, something the BBC frequently implies. In this instance, it’s curious that a recent episode of the BBC Sounds series on 39 Ways to Save the Planet is entitled Polluter Pays, in which the Oxford scientist Myles Allen argues that essentially all we need to do to sort out climate change is to force oil companies to suck CO2 out of the air. If he is right, then there is no need to keep the remaining fossil fuels in the ground – we could dig them up, use the energy, capture the CO2, and store it underground. Capturing the emissions at the point of combustion is cheaper than extracting them from thin air, but most of the emissions (about 90%) associated with humanity’s use of oil and gas occur far away from the refineries – in the vehicles we drive, the planes we fly in, and the buildings we heat. So in order to sort out climate change, the industry will need to rely primarily on thin air retrieval, also known as direct air carbon capture and storage (DACCS).

As variously noted – including in this blog in March 2020 – Allen’s idea requires a lot of money and energy, quite apart from international regulation of the oil majors and international agreement on how and where to store all the CO2. Money: based on the Committee on Climate Change’s estimates for the costs of DACCS of CO2 (6th carbon budget), we would be looking at thousands of pounds per person on the planet (more for rich Westerners presumably). Energy: to suck an amount of CO2 from the atmosphere that is comparable to what we currently put into the atmosphere (about 35 billion tonnes per annum) would increase global primary energy consumption by 10-20% just to operate the vacuum cleaner.

In the Polluter Pays podcast, there is the curious suggestion that if oil companies try to push up prices to cover the cost (several trillions of pounds per annum), they could be out-competed by renewables. Which alas would defeat the whole purpose, as they wouldn’t be around any more to remove the CO2. For this to work, everyone will end up paying as the cost dwarfs oil company financial reserves; “polluter pays” is largely a myth, even if we use oil company reserves as an initial down payment.

To be fair, no-one knows how much CCS capacity (including DACCS) will be in place in 2050. The UCL study is probably more sensible, and certainly more mainstream; and it avoids one of the pitfalls of Allen’s idea, which is that no-one else does anything because they believe in a technological miracle put into effect by oil companies. Either way, it’s a striking coincidence of diverging scientific opinions, which the BBC doesn’t seem to notice in its reporting.

Descriptions matter. As the seriousness of climate change becomes more evident, the way it is depicted will influence our response. Here are a few examples, with some potential repercussions.

The hockey stick curve

The image of a hockey stick lying on its back is often used to describe the atmospheric concentration of carbon dioxide over the last thousand years. The curved end pointing upwards at the right correlates very well with consumption of fossil fuels since the Industrial Revolution and with changes in global temperature. It is an image that has been extensively employed to refute climate deniers – how can they not see the obvious impact that human activity is having?

Certainly the strength of the relationship has helpfully convinced most people that global heating is man-made. But there is a downside: it also suggests to many that it’s entirely about CO2. A recent video by Extinction Rebellion (https://youtu.be/w3yRv1B8Y-w) is a case in point; in the video, one of the presenters claims that temperature levels were essentially benign before the 19th century because CO2 levels were flat and that if we curb CO2 emissions then climate change can be halted.

This is something of a misinterpretation. Before the 19th century, human beings were emitting greenhouse gases – mainly through agriculture – but at a level that the rest of the natural world could counter, through absorption by oceans and land. Since the IR, greenhouse gas emissions have increasingly exceeded the capacity of this natural response. But that’s all emissions, which include water vapour, methane, nitrous oxide, ozone, chlorofluorocarbons and hydrofluorocarbons (few of which I know anything about). Up until roughly the middle of the 20th century, GHG emissions from agriculture still exceeded human CO2 emissions, but the latter had broken the camel’s back, as it were.

Though CO2 is the main GHG, it’s wrong to conclude that only CO2 matters. Out of roughly 50 billion tonnes of GHG emitted annually, around 20 billion tonnes are other GHG, i.e. not CO2. We can influence global heating by reducing these other GHG – indeed, for us as individuals, our diet is probably the single biggest factor. Equally, temperatures could still rise alarmingly if we control CO2 but allow the other GHG to increase.

In the final years of the apartheid regime in South Africa, Barclays Banks was singled out for criticism in the media due to its financial involvement. Many (most?) other banks that escaped censure were also involved; they just weren’t as big as Barclays. CO2 is the Barclays of the GHG, so to speak, but all of them need to be tackled.

The budget

The budget is a metaphor used to shock governments into action. There is, according to this idea, a limited amount of GHG that we can emit before it is too late. Indicatively, we have about 500 billion tonnes left in the budget, which we will use up in around 10 years at the current rate of emissions. If we go over budget, according to this logic, then we are f****d.

Maybe shock is an effective tactic, but again there is a downside: if we declare ourselves bankrupt, we essentially give up. Yet atmospheric temperatures are not predestined to rise indefinitely. In the most optimistic scenarios of the IPCC’s latest report (August 2021), global temperatures start to fall, albeit slowly, post 2050. In later decades and centuries, the fall could be as exponential as the increase is today.

The earth is dynamic and nothing is permanent. Today’s emissions may be absorbed tomorrow: whilst CO2 itself potentially lasts for centuries, it does not follow that it has to reside in the atmosphere. Oceans, woods, or human carbon capture technology might suck it out. So let’s not despair, or ever declare ourselves bankrupt.

The overcrowded airport

Here is a better metaphor, used by the climate scientist David Mackay. Exasperated by journalists claiming that human emissions were a small fraction of those from the oceans and biosphere, Mackay compared the situation to a busy airport, one set up to deal with 1000 passengers an hour. If arrivals increase, say, to 1050 per hour, then the airport will rapidly become dysfunctional, even though the extra 50 are few compared to the original 1000.

This metaphor helpfully gets across the idea of a natural balance and our disruption of the balance. It also conveys a sense of the world’s dynamism. The metaphor could be extended – dynamic ‘feedback’ could be for the better or the worse. In the airport, fights might break out amongst frustrated travellers; in the world, rising temperatures might release methane from the oceans and permafrost. Bad news potentially. Or the airport might recruit more staff at short notice; natural mechanisms might adapt to become greener and better able to absorb GHG. Good news potentially.

This is not well understood. But in the knowledge at least that nothing will last forever, and with the prospect that our great-grandchildren might just about witness an improving climate, it is worth doing what we can and never giving up.