The Economist, a business magazine, has recently published an article on the IPCC's climate change report. The article also contains the same information that I wrote about the other day about the need to focus more on methane gas. According to the IPCC report, it is likely inevitable that temperatures will have risen by more than 1.5 degrees Celsius by the middle of this century compared to the end of the 19th century.
Suppose we had only considered the greenhouse effect of carbon dioxide alone. In that case, the globe is already 1.5 degrees Celsius hotter, but it has not yet reached 1.5 degrees Celsius because other cooling factors have offset it. For example, there is the fact that Sulphate aerosols from coal-fired power generation and organic carbon and black carbon from cooking with firewood and vehicles are blocking the sun's energy and dampening the greenhouse effect. This cooling effect is about 0.4 to 0.5 degrees Celsius, without which the temperature would already have been 1.5 degrees Celsius by now. Particles that block the sun's energy do exist in nature, but it is thought that humans produce about 10% of the total. These particles can rise more than 60 kilometres above the surface and drift for years, depending on the circumstances. Just looking at carbon dioxide and this cooling factor, it is clear that climate change is difficult to predict.
Overlaying warming and cooling factors other than carbon dioxide and soot has been the work of climate change modellers worldwide. The effects are still uncertain, but more manageable factors can be used to limit climate change. Recently, methane gas has attracted particular attention. This is because it is 30 times or more potent than carbon dioxide and, unlike carbon dioxide, controlling methane is unlikely to reduce human activity. Methane gas is released into the air from landfill sites, sewage treatment plants, and animal manure. Extracting methane gas from these human activities does not inhibit social activity, but it does not hinder economic activity, as methane is unused renewable energy. And if we can curb this methane, we can curb global warming faster than we can curb it by carbon dioxide. So there's a lot of focus on reducing methane now, and I think it's going to be discussed more than ever at the climate change conference in November. I hope this is an opportunity for biogas to get a bit more attention.