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Are Humans Facing Near-Term Human Extinction Due to Global Warming?

I have been studying the science of global warming with a passion since the late 1970s and earned a degree in Environmental Science in 1992.

A dog sled crossing a melting ice sheet that has turned into a lake

A dog sled crossing a melting ice sheet that has turned into a lake

It is a stark question, but one that needs to be asked because global warming is kicking into high gear and it is quickly becoming the only question that really matters: Are humans facing near-term human extinction due to global warming? By near-term, most climate scientists who ponder this question mean within the next 100 to 200 years, whereas some of the more pessimistic climate scientists ponder whether humans may only have a few decades or even years left on Earth before our life-sustaining environment becomes so inhospitable that it can no longer support our Homo sapien species that has proliferated on Earth for hundreds of thousands of years.

Looking back on the history of life on Earth, the main driver of species’ extinctions have been changes in climate over time that species could not adapt to, even when provided long spans of time to adapt. Given the unnaturally fast rate of global warming climate change now occurring, humans would have to adapt to the rapid loss of habitat and food sources, as well as all the other impacts, at an unprecedentedly fast speed. Adding to concerns regarding our survival as a species, pessimists point out that Homo sapiens are the last of several humanoid species (Neanderthals, Homo erectus, etc.) that made Earth their home for millions of years until these prior humanoid species eventually went extinct because they could not adapt to their environment and competition for food.

Why the Concern Now About Our Survival as a Species?

While some scientists started raising concerns about the burning of fossil fuels eventually warming the Earth’s atmosphere as far back as the middle 20th century, a consensus among scientists that global warming is a problem we have to address didn’t form until the later part of the 20th century.

Now that we’re progressing through the 21st century, why are some in scientific circles raising concerns about our near-term survival as a species? In recent years, the effects of global warming have become exceedingly extreme. In fact, from record-breaking heatwaves to unprecedented forest fires to melting polar ice sheets, the effects of global warming are occurring faster than the scientific community had projected they would just a decade or two ago. The concern about our viability as a species on Earth is due to the fast-developing effects of global warming. If we don’t address the causes of global warming or take mitigative actions, it could transform into runaway global warming that would heat up the Earth so rapidly that humans and many other species will likely be imperiled.

Many scientists wrongly had confidence that mankind would come to its senses when faced with the stark reality that our survival as a species is threatened and we’d collectively take actions to avert catastrophic global warming by discontinuing our burning of fossil fuels and replacing them with renewable non-carbon energy sources. However, despite some tepid efforts to cut carbon emissions, such as the 2016 Paris Agreement, it appears that due to a combination of ignorance and a concerted effort by the fossil fuels industry to stop any efforts to move away from carbon-based products, we will likely not address our continuing release of global warming gases into Earth’s atmosphere until it’s too late and the global warming we’ve experienced in recent decades transforms into irreversible and catastrophic runaway global warming.

This will occur because human-caused global warming will eventually trigger natural climate warming feedback loops to take over. At that point, global warming will be like an unstoppable runaway train, as the Earth’s atmospheric temperatures rise to life-threatening levels. These warming feedback loops include such things as releases of global warming gases from melting polar ice sheets and from frozen methane deposits beneath the oceans, as well as the loss of polar ice causing the Earth to absorb more of the sun’s heat energy. All of which will cause additional warming, which then results in additional releases of global warming gases that will cause additional global temperature rises in an unstoppable loop that will continue until the planet is warmer than it has been in many millions of years (long before humans existed).

Such rapid and uncontrollable warming of Earth’s atmosphere could warm the planet by 4 to 5 degrees Celsius (7 to 9 degrees Fahrenheit) within the current century and perhaps eventually lead to a planet that is 8 to 9 degrees Celsius (14 to 16 degrees Fahrenheit) warmer than it was before humans started burning fossil fuels in large quantities starting in the 19th century.

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Some might wonder, what’s the big deal if the planet is 4 to 5 degrees Celsius or even 8 to 9 degrees Celsius warmer than it has been as humans evolved on Earth? After all, many parts of the planet routinely experience temperature swings of this magnitude on a daily or weekly basis. There are several ways that rapid global warming on a planetary scale could threaten human survival.

  • Warming is not evenly distributed. Some areas, including currently farmable land, will warm well in excess of the global average, which would lead to desertification and crop failures. This would obviously imperial humans due to massive food shortages.
  • Oceans, another major source of food that humans need to survive, are impacted by rising global temperatures, as higher ocean temperatures lead to acidification of ocean water, which will eventually lead to massive die-offs of sea life that provide much-needed food for humans.
  • Water resources will completely dry up in many arid parts of the world, making those areas uninhabitable.
  • Dwindling food and water resources will inevitably lead to wars between competing nations that could be catastrophic.
  • Humans can’t survive at wet-bulb temperatures above 35 degrees Celsius (95 degrees Fahrenheit), even in the shade, as the human body loses its ability to cool itself off. Higher global temperatures and the higher humidity levels that will occur with the higher temperatures could make large parts of the Earth uninhabitable due to wet bulb temperatures that are lethal.
Guy R. McPherson, Ph.D., a former Ecology professor from the University of Arizona,  is a big proponent of the view that humans will soon become extinct due to global warming.

Guy R. McPherson, Ph.D., a former Ecology professor from the University of Arizona, is a big proponent of the view that humans will soon become extinct due to global warming.

Would Runaway Global Warming Actually Lead to Human Extinction?

It’s a very big step go from runaway global warming to the extinction of all human beings on Earth. Humans possess the intellectual skills necessary to design and build technologies that can help us adapt to climate change. We’re also able to move to places with more hospitable climates. However, some scientists are concerned that humans will not have time to adapt to the quick pace of runaway global warming and some of the impacts will be too harsh for us to survive.

If farmlands and oceans are no longer capable of providing food for humans, where will we turn to obtain life-sustaining food? It is possible that humans could migrate towards the poles and try to farm on land in those areas that is freed up from the ice. However, it is unclear if the currently frozen areas in and around the polar regions will have topsoil suitable for farming. What about freshwater fish? Unfortunately, freshwater lakes and rivers will also undergo acidification that will likely wipe out most or all fish species that can provide humans nourishment. Our only hope might be some sort of synthetic food that is created in factories using basic elements (a technology that is certainly viable).

There will be other life-threatening factors that humans will face in a fast warming world. Massive fire balls from methane releases will create havoc for humans. These fireballs will start enormous forest fires driven by the warmer and in many places a more arid world, which will cause turmoil for humans. A lack of freshwater in areas that undergo desertification will make survival impossible in such areas. Wars over dwindling resources will be fought out of desperation and could end in catastrophe.

The stress of a warmer world will weaken human immune systems. If industrial society collapses or is greatly reduced, healthcare and medicines might become very limited, lowering life expectancy dramatically. Humans that survive all the dangers associated with runaway global warming might succumb to pandemics that will likely sweep the world as opportunistic pathogens take advantage of weakened human systems and cause a large loss of life in the remaining human populations.

Will Earth overheat and threaten human survival?

Will Earth overheat and threaten human survival?

Near Term Human Extinction Poll

Time To Wake Up! If We Don’t Act On Climate Change, Human Civilization Could End By 2050

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 John Coviello

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