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One billion deaths over the next century from climate change: study

A recent study from the University of Western Ontario suggests that climate change could cause one billion premature deaths over the next century if global warming reaches or exceeds 2° Celsius.

Joshua Pearce, lead author of the study, points out that mainly richer humans will be responsible for this catastrophe, and poorer communities will be the hardest hit. 

“Such mass death is clearly unacceptable. It’s pretty scary really, especially for our children,” said Pearce. “When climate scientists run their models and then report on them, everybody leans toward being conservative, because no one wants to sound like Doctor Doom. We’ve done that here too and it still doesn’t look good.”

Aggressive energy policies needed

The oil and gas industry, accounting for over 40 percent of carbon emissions, has a massive impact on the lives of billions of people, especially those in remote and low-resourced communities. 

The study recommends aggressive energy policies for immediate and substantial decreases in carbon emissions, urging government, corporate, and citizen action to expedite the decarbonization of the global economy and minimize projected human deaths.

The comprehensive review, co-authored by Richard Parncutt from the University of Graz in Austria, involved an analysis of over 180 scientific articles. 

The 1,000-ton rule

The experts found that the peer-reviewed literature on human mortality costs of carbon emissions converged on the “1,000-ton rule,” an estimate that one future premature death is caused every time approximately 1,000 tons of fossil carbon are burned.

Pearce emphasized the importance of understanding the gravity of the situation: “Energy numbers like megawatts mean something to energy engineers like me, but not to most people.” 

“Similarly, when climate scientists talk about parts per million of carbon dioxide, that doesn’t mean anything to most people. A few degrees of average temperature rise are not intuitive either. Body count, however, is something we all understand.”

One billion premature deaths

“If you take the scientific consensus of the 1,000-ton rule seriously, and run the numbers, anthropogenic global warming equates to a billion premature dead bodies over the next century. Obviously, we have to act. And we have to act fast.”

Pearce and Parncutt argue that by challenging the language and metrics of global warming, policymakers and industry leaders can better comprehend the harsh realities of fossil fuel dependence. 

“As predictions of climate models become clearer, the harm we are doing to children and future generations can increasingly be attributed to our actions,” said Pearce. This recognition means that greenhouse gas emissions liabilities can no longer be ignored.

A race to save lives

To limit future liabilities and save lives, the study suggests humanity must cease burning fossil fuels as quickly as possible by adopting a more aggressive approach to energy efficiency and renewable energy. 

The study outlines key areas to prioritize in energy policy to mitigate climate change:

  • Enhance energy conservation and efficiency, and rationalize energy use, supported by government programs for industrial, agricultural, transportation, residential, and household users.
  • Completely replace high carbon fuels (coal, oil, and natural gas) with zero carbon content fuels (e.g., hydrogen, electricity) from renewable energy sources like hydropower, wind, geothermal, biomass, and solar, scaled and distributed to create resilient power networks.
  • Develop technologies for carbon waste management and natural capture and storage of CO2, including carbon sequestration and regenerative agriculture.
  • Replace carbon subsidies with carbon taxes.

“The 1,000-ton rule is only an order of magnitude best estimate,” said Pearce. “The number of caused deaths will likely lie between a tenth of a person and 10 people per 1,000 tons. Regardless, the bottom line that we need to act fast is still crystal clear.”

“Global warming is a matter of life or death for a billion people. Almost everyone agrees that every human life is valuable, independent of age, cultural or racial background, gender, or financial resources. Therefore, the energy transition will have to change much, much faster, starting now.”

More about the global warming tipping point

If global average temperatures rise more than 2° Celsius above pre-industrial levels, it could result in a range of severe and potentially irreversible impacts on the environment, societies, and economies.

This threshold has been set by the Paris Agreement as a target to prevent catastrophic climate effects, but even a 2° Celsius increase will bring about notable changes.

Some potential consequences of a temperature rise of more than 2° Celsius include:

Sea level rise

Melting polar ice caps and glaciers, along with the thermal expansion of seawater, will cause sea levels to rise. This could inundate coastal cities and communities, leading to displacement of populations and loss of infrastructure.

Increased weather extremes

There would be an increase in the frequency and intensity of extreme weather events such as hurricanes, typhoons, heatwaves, droughts, and heavy rainfall. These changes can lead to loss of life, property damage, and economic challenges.

Ocean acidification

The uptake of additional CO2 by the oceans will make them more acidic, affecting marine ecosystems. Coral reefs, vital for marine biodiversity, will be particularly vulnerable.

Loss of biodiversity

Many plant and animal species will be unable to adapt to rapid changes, leading to habitat loss and potential extinction. This will disrupt ecosystems and the services they provide to humans.

Economic impacts

Agriculture will face challenges from changing precipitation patterns, increasing temperatures, and shifting climate zones. Some regions may benefit temporarily, but many others will experience declines in crop yields. Fisheries will also be affected due to changes in ocean temperatures and currents.

Social and political impacts

Resource scarcity, particularly water in some regions, could lead to conflicts. There will also be challenges from climate-induced migration as people move from areas that become uninhabitable or economically untenable.

Shift in habitats and disease vectors

As temperatures rise, disease vectors like mosquitoes could move into new areas, potentially spreading diseases like malaria or dengue to previously unaffected populations.

Feedback loops

Some processes might amplify the effects of global warming. For example, as Arctic permafrost melts, it releases methane, a potent greenhouse gas, which can further accelerate warming.

Irreversible changes

Some impacts may push components of the Earth system past tipping points, leading to long-term or permanent changes. Examples include the loss of the Greenland ice sheet or the disruption of the Atlantic Meridional Overturning Circulation.

Ecosystem changes

Forests, particularly the Amazon, could face extreme stress or dieback, transforming from carbon sinks to carbon sources.

Addressing this challenge requires global cooperation, rapid decarbonization of the economy, and investment in adaptation and mitigation strategies. If the world overshoots the 2°C target and then later tries to bring temperatures down, some of the changes might be irreversible or carry long-lasting consequences.

The research is published in the journal Energies.

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