The solution to Branson's problem (not to mention our, global, problem)
is closer to hand than we could ever have imagined. It is, quite
simply, stop breathing; or at least breathe less.

The average person takes 24,000 breaths a day, breathing in
approximately 6g of carbon dioxide, but breathing out around 800g
during the same time. Over a year, you personally will add a net 290kg
of CO2 to the atmosphere, just by exhaling. Multiply that by a global
population of 6.5 billion and it adds up to a criminal 1.88 gigatonnes.

If we each merely cut out one breath in three, we could decrease the
amount of CO2 entering the atmosphere each year by a staggering 0.63
gigatonnes. That's 0.63 billion tonnes - the same effect as saving 5
million acres of land (an area the size of Wales) from deforestation,
or recycling 192 million tonnes of waste instead of trashing it.

But we don't want to stop there. Let's get really ruthless.

Perhaps the most carbon efficient solution would be to eliminate those
members of the population taking the most breaths and therefore
expelling the most carbon dioxide.

Intuitively, you might expect these to be the sorts of idle layabouts
who wouldn't know what a treadmill was if it hit them in the face. With
their high resting heart rates and shallow, wheezing breaths, they must
be the least environmentally sound.

But that's not the case. Being as there is no obvious difference
between the metabolic rates of the honed and toned, and the squashy and
sluggish, we all burn about the same amount of carbon whilst resting.
However, all that time that the super-fitties among us spend
exercising, they're guzzling extra oxygen and belching out tonnes of
CO2.

When we undertake strenuous exercise our metabolic rate tends to
increase by at least 50%. So during a 30-minute bout, we could be
expelling an extra 8.3g of carbon dioxide.

Perhaps that doesn't seem like much, but by our calculations, if we
exercised as we were supposed to ? about 30 minutes, five times a week
? this would add up to another 1.3kg a year. Across the world
population, that's a lung-busting 14 million tonnes of extra CO2 every
year.

And just to make matters worse, your body continues to metabolise at a
higher rate long after you cease exercising, pumping out increased
levels of carbon dioxide for anything up to 36 hours.

Doctors Impey and Steer prepare to win the big prize in the Virgin
Earth Challenge.

Doctors Impey and Steer get into training to receive their big winnings

So the key to reversing climate change and saving the planet is simple:
do nothing. Absolutely nothing. In an ideal world, we'd all just sit
around keeping our breathing rates as low as possible, skipping the odd
breath here and there just to help matters along. That way we'd all be
.

And there's an extra benefit to the global atmosphere.

As our enforced lethargy leads us to pile on the pounds, we'll act as
carbon sinks ? tying up potentially dangerous atmospheric carbon (via
plants and hopefully an animal or two) as ever-so-becoming fat deposits.

But, before you revel in the excuse to leave your trainers to gather
dust, the amount of carbon dioxide you would save by not exercising is
nothing compared to what you'd save by running somewhere instead of
driving.

And one final thought: even if CO2 levels were to be stabilised
quickly, global temperatures would continue to soar for years to come.
So, even though we've helped solve Branson's challenge, in terms of
seeing an ? don't hold your breath.