There is an interesting review on climate change (Matthews & Wynes, 2022, Science 376: 1404 – 1409). One point that comes up early is how did this sneak up on us? If you look at the graph on global temperatures, you will see that the summers in the 1940s were unusually hot, and the winters in the 1960 – 1980 period were unusually cool, with the net result that people living between 1940 – 1985 could be excused for thinking in terms of extremes instead of averages that the climate was fairly stable. As you will recall, at 1990 there was a major conference on climate change, and by 1992 goals were set to reduce emissions. It is just after this that temperatures have really started rising. In other words, once we “promised” to do something about it, we didn’t. At 1960 the CO2 levels in the atmosphere were about 320 ppm; by 1990 the CO2 levels were about 365 ppm, and at 2022 they are about 420 ppm. The levels of CO2 emissions have accelerated following the treaty in which much of the world undertook to reduce them. Therein lies out first problem. We are not reducing emissions; we are increasing them, even though we promised to do the opposite. (There was a small reduction in 2019-2020 as a result of the Covid lockdowns, but that has passed.) In short, our political promises are also based on hot air.
The current warming rate is approximately a quarter of a degree Centigrade per decade, which means that since we are now about 1.25 degrees warmer than the set 1850 baseline, we shall hit the 1.5 degrees warming somewhere just after 2030. Since that was the 1990 target not to be exceeded, failure seems inevitable. According to the models, to hold the temperature to 1.5 degrees C above our baseline we must not emit more than 360 Gt (billion tonne) of CO2. The IPCC considers we shall emit somewhere between 400 -650 Gt of CO2 before we get carbon neutral (and that assumes all governments actually follow up on their stated plans.) What we see is that current national targets are simply inadequate, always assuming they are kept. Unfortunately, there is a second problem: there are other greenhouse gases and some are persistent. The agricultural sector emits nitrous oxide, while industry emits a range of materials like sulphur hexafluoride, which may not be there in great quantity but it is reputedly 22,800 times more effective at trapping infrared radiation than CO2, and it stays in the atmosphere for approximately 3,200 years. These minor components cannot be ignored, and annual production is estimated at about 10,000 t/a. It is mainly used in electrical equipment, from whence it leaks.
Current infrastructure, such as electricity generators, industrial plant, ships, aircraft and land transport vehicles all have predictable lifetimes and emissions. These exceed that required to pass the 1.5 degree C barrier already unless some other mitigation occurs. Thus, the power stations already built will emit 846 Gt CO2, which is over twice our allowance. People are not going to abandon their cars. Another very important form of inertia is socio-political. To achieve the target, most fossil fuel has to stay in the ground, but politicians keep encouraging the development of new extraction. The average voter is also unhappy to see major tax increases to fund things that will strongly and adversely affect his way of life.
One way out might be carbon capture. The idea of absorbing CO2 from the atmosphere and burying it may seem attractive, but how is it done, at what cost in terms of money and energy required to do it, and who pays for it? Planting trees is a more acceptable concept. In New Zealand there is quite a bit of land that was logged by the early settlers, but has turned out to be rather indifferent farm land. The problem with knowing whether this is a potential solution or not is that it is impossible to know how much of such land can be planted, given that a lot is privately owned. However, planting trees is realistically something that could help, even if it does not solve the problem.
The article seems to feel that the solution must include actions such as lifestyle changes (carless days, reduced speed limits, reduced travel, a reduction of meat eating). My feeling is this would be a very difficult sell in a democracy, and it is not exactly encouraging to persuade some to purchase electric vehicles then be told they cannot use them. The article cites the need for urgency, and ignores the fact that we have had thirty years where governments have essentially ignored the problem. Even worse, the general public will not be impressed to find they are required to do something that adversely affects their lifestyle, only to find that a number of other countries have no interest in subjecting their citizens to such restrictions. The problem is no country can stop this disaster from happening; we all have to participate. But that does not mean we all have to give up our lifestyles, just to ensure that politicians can get away with their inability to get things done. In my opinion, society has to make changes, but they do not have to give up a reasonable lifestyle. We merely need to use our heads for something better than holding up a hat. And to show that we probably won’t succeed, the US Supreme Court has made another 6:3 ruling that appears to inhibit the US Federal Government from forcing certain states to reduce emissions. We shall cook. Yes, this might be a constitutional technicality that Congress could clear up easily, but who expects the current Congress to do anything helpful for civilization?