Breathe …not so easy
We are fast approaching a time when humanity’s next breath may be its
Now that the United States Environmental Protection Agency (EPA) has
defined carbon dioxide as a pollutant under Section 202(a) of the Clean
Air Act, we should probably mutter “Beg pardon” whenever we respire.
On average, an adult human gulps down 250ml of oxygen per minute and
puffs out 200ml of carbon dioxide. With 6.6 billion human lungs at work,
that adds up to 2.16 trillion tons of CO2 a year.
Humankind’s carbon “breath print” accounts for as much as 9% of
global CO2 - roughly equivalent to driving 500 million cars. With the
United Nations estimating the world’s population will swell another 37%
by 2050, all those extra lungs would add another 824 billion tons/year
to the human breath print by mid-century.
Since air-breathing animals first appeared on Earth 600 million years
ago, CO2 and O2 levels have fluctuated (in the case of oxygen, from 16
to 35%). Before the Industrial Revolution, the human breath print wasn’t
such a concern since every human sigh and shout was part of Nature’s
The CO2 we expelled was absorbed by plants; the plants were eaten by
animals; the plants and animals were eaten by humans. But when we
started burning fossil fuels, we began introducing a huge new load of
carbon to the equation – carbon that had been sequestered since the days
of the dinos.
As the authors of Out of Thin Air: Dinosaurs, Birds and Earth’s
Ancient Atmosphere observe, four of Earth’s “Big Five” extinctions
occurred during high-CO2/low-O2 periods and even minor drops in oxygen
levels have been linked with “wholesale species disappearances”.
Many of Earth’s species are already experiencing massive die-offs
while others - from tigers to polar bears - are facing extinction. As
the seas absorb excess CO2, ocean acoustics are going haywire. The
racket of ship propellers and military sonar is becoming louder,
suggesting a future in which deafened dolphins will be dying in
progressively carbonated seas.
It’s not just our cars and factories that spew CO2. Our appetite for
meat is also breathtaking. The Food and Agriculture Organisation notes
that “meat and dairy animals now account for about 20% of all
terrestrial animal biomass”.
Livestock occupy 30% of the world’s land surface and generate 18% of
the world’s greenhouse gases (more than the transport sector). Even
worse, cow burps generate vast stores of methane (with 23 times the
global warming potential of CO2) and nitrous oxide (296 times more
heat-trapping than CO2).
Meanwhile, we’ve further disrupted the Carbon Cycle by replacing
CO2-storing prairies and forests with sprawling, methane-belching cattle
Because methane remains in the atmosphere for only a few years, the
quickest way to address global warming is to reduce methane emissions,
That’s why Dr Rajendra Pachauri, the world’s leading climate
scientist, has issued a global plea to stop eating meat. (It’s a simple
choice: Would you rather have a steak today or a stake in a sustainable
Meanwhile, the London School of Economics reports that investing in
contraception is five times cheaper than any “green-tech” solution to
climate change. (To be effective, contraception must begin in the North,
where the carbon footprint of a US teen is 20 times heavier than the
carbon bare-footprint of a Kenyan farmer.)
British scientist James Lovelock predicts that a CO2-stoked climate
calamity could claim 10 billion lives by the end of the century, leaving
only one billion survivors on a blighted planet.
As a reminder of the blessings of breath, one of the best ways to
celebrate Earth Day, 22 April, would be for everyone to just stop and
take a deep breath.
With Lovelock’s warning in mind, it’s clearly time to “suck it up”
and accept our responsibility for survival of life on this shared
planet. We are fast approaching a time when humanity’s next breath may
be its last gasp.