So said UN Secretary-General Antonio Guterres to the COP27 delegates on 7 November, reported by Forbes.
Originally published 11/7/2022
Update: I added text and the graphic, Impact of Climate Change On Human Health, to show the factors that will contribute to human population decline. These do not include decisions by young people to have fewer if any children.
Our understanding of the drivers of climate change is well-understood, but most people in developed counties nor their leaders want to give up their lifestyle of convenience, comfort, and profit. Yet, not addressing climate change will likely kill most of humanity during the next hundred years. The six charts, below, show how human population growth and industrialization created greenhouse gases that warm the planet, likely resulting in a 3oF temperature rise above pre-industrial levels by 2100 if left unchecked.
According to scientists, we have about seven years left to drastically curb our greenhouse gas output to avoid an irreversible tipping point. Methane is 80 times more heat-trapping than carbon dioxide over twenty years and 20 times more heat-trapping over a hundred years. This is because newly introduced methane molecules into the atmosphere are broken down by sunlight over 10 years, whereas carbon dioxide remains in the atmosphere for centuries unless recaptured by plants.
Climate change will reduce the human population due to factors shown in the following chart. Alternatively, we can minimize our decline with aggressive climate change initiatives. There is a current cholera pandemic that is worsened by flooding, the result of climate change.
One way or another human population must decline, and people will have to go back to living much as we did in the nineteenth century (what I call micro-industrialization), though with modern versions of electric trains and trolleys. Renewable energy cannot fully replace fossil fuel energy in the foreseeable future so we will just not have a lot of stuff, and most people will again be farmers.
What might micro-industrialization look like? It is hard to say since how we will utilize diminished energy resources is as much a political question as it is an engineering one. A New York Times article gives us a glimpse of how micro-industrialization might start.