Climate Change Will Bring More Death Than We are Used to Seeing
We will get used to it.
Photo by Abhishek Singh on Unsplash
The World Economic Forum Report: Quantifying the Impact of Climate Change on Human Health (2024) tries to quantify the impact of climate change on mortality. They estimate that by 2050, humanity will experience 14.5 million excess deaths due to climate change events. This only covers floods, wildfires, sea level rise, tropical storms, and heatwaves. This does not cover any secondary impacts of climate change due to famine, conflicts resulting from climate change, increased morbidity due to an increased outbreak of climate-related diseases, or other climate-related causes of death.
The authors note that developing countries will be disproportionately affected due to their dense populations living in low-lying coastal zones and large swaths of geography in these areas that have hot and dry climates. The quality of medical care people receive in developing countries will also play a role.
The report only looks at climate change as a cause of increased mortality and does not delve into the impacts of other planetary boundaries that we have crossed, or likely will cross by 2050. For example, the planetary boundary of ocean acidification has not been breached yet, but if it is breached, it would have devastating effects on life in the world's oceans. This would in turn have devastating effects on people.
The excess deaths from the breaching of all planetary boundaries by 2050 are likely much higher than the 14.5 discussed in the WEF report. I couldn’t find such a number anywhere, so if you see one, let me know and I’ll update this.
Source: World Economic Forum
The report does show that 2.0 billion people will have their health negatively impacted by climate change by 2050. Most notably, droughts will impact the health of about 1.1 billion people by 2050, about 1/8 of today's population. The report states that climate-induced impacts will account for a further $1.1 trillion in extra costs to healthcare systems, creating a significant additional burden on already strained infrastructures and medical and human resources.
This has all happened before.
To put these numbers in a bit of perspective, here is a chart showing some of the mass mortality events in human history.
Source: FastCompany
The Black Death of the 14th century reduced the world population from about 475 million to about 350 – 375 million. In parts of Europe, it took 80 – 150 years for populations to recover. The best analogs for climate change may be the World Wars of last century. We will likely see tens of millions of unnecessary deaths due to environmental degradation and extreme weather, with climate change being the most noteworthy, but by no means the only environmental reason behind these deaths. Those numbers are just up to 2050. If we haven’t done enough, those numbers will only grow.
Estimates range a great deal as to what impact climate change will have on the world’s population. Here are some of the highlights/lowlights.
The IPCC Sixth Assessment Report projects that the world population could be between 8.5 billion and 11 billion people by 2050.
One of the most apocalyptic predictions came in 2009 from, Hans Joachim Schellnhuber, from the Potsdam Institute for Climate Impact Research. He stated that if global warming reached 4C the human population would likely be reduced to about 1 billion. On a “happy” note, we are now well below projections of a 4C rise in temperatures. We currently sit at about 2.7C expected degrees of warming.
What is the carrying capacity of Earth?
The carrying capacity of Earth depends on our use of the planet’s resources. The more we use, the lower the carrying capacity. The less we use, the higher the carrying capacity. We can start with the Dasgupta Review – The Economics of Biodiversity, which states we are currently using Earth’s resources as though we had 1.6 Earths to use. To figure this out we divide Earth’s current population, about 8 billion by 1.6 and we get about 5 billion. So, Earth’s carrying capacity according to our current resource use is about 5 billion people.
We could also use Earth Overshoot Day, which this year is May 27th. I’m going to cheat a little and just say it is the end of May. I can solve for 8 billion * 5/12, which gets us to about 3.33 billion people as Earth’s current carrying capacity. Yikes!
If you split the difference between these two rough estimates, you get a number a little north of 4 billion, which is about half of the population of Earth now.
We are way on the dangerous side of overshoot, so you better believe a correction is coming. Degrowth is the answer to getting us off that trajectory and lowering the strain on the planet. This would allow for a somewhat smoother population correction.
I am not rooting for or advocating for population reduction. I am telling you that this is coming because I believe in physics and the wisdom behind the simple phrase; “If something is not sustainable, it will end.”
Mother Nature is going to take corrective action.
An even broader perspective.
Of course, much greater levels of death have happened before on Earth. We are now in the midst of the 6th mass extinction in the Earth’s history. It is just a matter of how much ends up becoming extinct. Probably not us, but we will be responsible for it. The history of mass extinctions throughout Earth’s history doesn’t paint a pretty picture. We are the first species to recognize we are in the middle of a mass extinction. That hasn’t stopped us from causing it, and we don’t look like we have any plans to stop it.
Source: (The Conversation/CC BY-ND 4.0)
Once a mass extinction gets started, it is hard to put on the brakes. We have a long way to go. (That is not a statement meant to comfort, but one meant to show that we are early in this mass extinction).
regarding carrying capacity. The amount of nature we leave for other species also has to be considered. Estimated requirements are between 30 and 50 %. In addition, the 1.6 earth's cited is an acknowledged conservative estimate. We are actually using more than that number indicates - we are likely much closer to putting demands on nature that are roughly double what can be regenerated annually. So roughly halving the estimates you provided gives us a much better idea of global carrying capacity. Another way to think about it is there are roughly 12 billion hectares of productive earth surface (from where we get all our food, food and fibre, and that absorbs our wastes). And there are currently 8 billion of us. That means we are using 1.5 global hectares each - when we should be using only half that - to allow for other species. How well do you think you could manage on a .75 global hectare? This is why population levels are so important in this process of degrowth.
Matt, thank you so much for this breakdown. This needs to be said, and I appreciate all the research you've put in. Another factor in what we consider our carrying capacity is how much of the Earth's ecological production/land/biomass we reserve for not-directly-human-serving species (ex. excluding cattle). This is both a "shallow" ecological question (ex. how much biodiversity do we need to be relatively "safe" from catastrophic ecosystemic changes?) and a "deep" ecological question (ex. what rights should other species/ecosystems have?). As you note, we're unique in that we don't have to overuse our resources till our population plummets (like mice). We can make both strategic and ethical choices, which necessarily includes our ethics toward other life.