Climate change is causing a rise in temperatures, hurricanes that are stronger, more intense floods, and an increase in wildfire seasons. Scientists warn that climate change is a major problem facing humanity. However, climate change could lead to humans becoming extinct if they don't act quickly.
Scientists have predicted a variety of catastrophic scenarios if climate change isn't controlled. But if we only consider the direct effects, there's good news: it's unlikely that it will cause our extinction.
"There is no evidence that climate change scenarios would make human beings extinct," Michael Mann (a Penn State professor of atmospheric sciences and author of "The New Climate War" (PublicAffairs 2021), said to Live Science via email.
Research shows that it is possible that climate change could still pose a threat to the lives of hundreds and millions of people. This would be due to the fact that water and food scarcity will increase, which can lead to societal collapse and create the conditions for conflict.
Related: Could we ever remove enough carbon from the atmosphere to stop climate changes?
Are you too hot?
Through the burning of fossil fuels, humans are increasing greenhouse gas levels, including carbon dioxide and methane. These gases trap heat from the sun and cause global temperatures to rise. This is putting humanity on an extremely dangerous path.
According to Luke Kemp, a researcher at the Centre for the Study of Existential Risk, the University of Cambridge, the runaway greenhouse effect is the most likely way that climate change impacts can directly cause human extinction. This happens when a planet becomes trapped in a positive feedback loop of warming. It absorbs more heat and loses less, until its oceans disappear and the planet cannot sustain life.
The runaway greenhouse effect does not appear to be a plausible scenario for climate change on Earth. The planet must have carbon dioxide levels at least a few thousand parts per millions (Earth has just over 400 parts/million). Or, it will release a lot of methane. NASA's Jet Propulsion Laboratory research scientist Brian Kahn told NASA in 2018.
Live Science previously reported that Venus does not have the runaway greenhouse effect. However, it is closer to the sun and has thicker, more carbon dioxide-rich atmosphere which traps more heat. Mann stated that although climate doomists make similar claims often, science does not support the idea of runaway warming. "There is no reason to exaggerate climate danger. It is clear enough that the climate threat is serious enough for us to take drastic action.
An image of Earth taken from space by a fish-eye lens. (Image credit: Getty / Nuttawut Uttamaharad / EyeEm)
Mann claims that a global temperature rise of 5.4 degrees Fahrenheit (3° Celsius) or greater could cause a collapse in our social infrastructure, massive unrest, and conflict. This could then lead to a future similar to some Hollywood dystopian movies.
Climate change can lead to a social collapse by increasing food insecurity. Live Science reported that warming the planet can have a variety of adverse effects on food production. This includes increasing the water deficit, thereby decreasing food harvests, and other negative consequences. According to a February 21st study in Climatic Change, food production losses can lead to increased human deaths, economic loss, and socio-political instability. These factors could trigger the collapse of institutions and increase the risk for societal collapse.
Related: Was the Earth ever this hot?
Past extinctions, and collapsing
Kemp examines the possibility of climate change and previous civilization collapses. He said that catastrophes and extinctions almost always involve many factors. However, he believes climate change, if humans were to become extinct, would be the most significant factor.
"If I had to choose, which factor is most likely to lead to human extinction in the future?" Kemp stated that climate change is the most important contributor to human extinction in the future.
Kemp claims that all major mass-extinctions in Earth's history involved some form of climate change. These events include the cooling that occurred during the Ordovician– Silurian extermination about 440 million year ago, which wiped out 85%, and the warming that occurred during the Triassic– Jurassic mass extinction 200 million years later, which killed 80%, Live Science previously reported. Climate change has also had an impact on the fates of our ancestors, especially in recent years.
Kemp stated that Homo sapiens is not extinct. However, Kemp noted that there are other hominid species that have gone extinct like Neanderthals. "And it seems that in all of these cases, climatic changes plays some role."
Although scientists don't know the reason Neanderthals became extinct around 40,000 years ago. However, climatic fluctuations and extreme temperature changes seem to have caused them to become smaller and more fragmented. Live Science reported that a small drop in Neanderthal fertility rates may have contributed to their extinction.
At the Natural History Museum in London, a male Neanderthal replica. (Image credit: Chettaprin.P/Shutterstock.com)
The collapse of human civilizations in the past has been attributed to climate change. For example, the collapse of ancient Greece around 3,200 years ago was caused by a 300-year-long drought. However, the disappearance of Neanderthals and collapsed civilizations does not mean that humans will die. Despite the fall of many civilizations, humans have survived past climate fluctuations and are still alive today all over the globe.
Homo sapiens has proven to be adaptable and capable of coping with all climates, whether they are hot, cold or dry, wet or dry. According to Smithsonians National Museum of Natural History, we can draw on resources from many animals and plants, and then share them with each other to survive in a changing world.
Related: How could 2 degrees of warming make a difference to the planet?
We live in an interconnected, global society today. But there are reasons to believe that our species may survive the collapse. The study, published in Sustainability on July 21, identified the countries that are most likely to sustain their complex way of living and survive a global social collapse. Because of their low temperatures and low variability, five island countries (including New Zealand and Ireland) were selected because they can sustain agriculture. This is in addition to the fact that they are more resilient to climate change.
New Zealand is expected to perform well under other favorable conditions such as a low population, high quality agricultural land, and reliable domestic energy. Even if climate change causes a collapse of global civilization, humankind will likely continue to exist, at least in certain areas.
We must take responsibility for ourselves
Climate-driven conflict is the last scenario you should consider. Kemp explained that a future where there is a decrease in resources could lead to wars that are likely to threaten the human race. Kemp stated that there are reasons to be worried about the future. As water resources decrease and scarcity increases, and general living conditions become more difficult, then the risk of nuclear war suddenly becomes greater.
In other words, while climate change may not cause human extinctions, it could result in events that threaten hundreds of millions, or even billions of lives. A study published in Science Advances in 2019 found that nuclear war between India and Pakistan could result in 50 million to 125 millions deaths in these two countries, each with only a fraction of the world’s nuclear weapons. A nuclear war could also alter the climate by lowering temperatures and filling the atmosphere with smoke. This would threaten food production around the world and possibly cause mass starvation.
What's next?
Although avoiding total extinction may not sound like a silver lining to climate change, there are still reasons for optimism. Experts agree that it's possible to prevent the worst-case scenario by making significant reductions in greenhouse gas emissions.
Mann stated, "It's up to us." "If we fail significantly to reduce carbon emissions in the next decade, we are likely to worsen already dangerous extreme weather events, flood of coastlines around world due to melting of ice and rising water level. This will increase our dependence on limited resources, as a growing global populace competes for food, water, and space because of climate change impacts. We can prevent the worst effects if we act now.
Original publication on Live Science
