Surviving C21 - Julian Cribb
Global warming is edging perilously close to out-of-control, according to scientific reports from round the planet.
This means that time is running out if we want to preserve our world
in a stable, healthy and productive state, capable of feeding and
supporting humanity.
The great concern is the dramatic rise, over the last three years, in
methane levels in the atmosphere. Methane is a gas with 28 times the
climate-forcing power of carbon dioxide. Scientists estimate there may
be as much as 5 trillion tonnes of it locked in permafrost and in
shallow ocean deposits.
Scientific evidence is amassing that, as the planet warms due to
human activity, these vast reserves of greenhouse gas are now starting
to melt and vent naturally. The Earth’s past history – in an event 50
million years ago known as the Palaeocene-Eocene Thermal Maximum, or
PETM – shows this could unleash runaway global warming by driving up
planetary temperatures by as much as 9 or 10 degrees Celsius.
At such temperatures, many scientists consider there is a high risk
of the planet becoming uninhabitable to humans and large animals.
Certainly it would eliminate agriculture and most food production and
unleash the mass migration of hundreds of millions of starving refugees.
Runaway heating and nuclear war are the two most likely triggers for
human extinction – and it is time everyone took them both a lot more
seriously.
Reports of methane escaping into the atmosphere have been growing
steadily, ever since a group of students demonstrated the risks by
setting fire to venting Arctic gas in 2008. However, scientists report a sudden surge in global methane emissions in the last three years, 2014-16.
The rise in methane has been attributed mainly to human activities
like cattle raising, rice farming, gas and coal extraction – but there
is now disturbing evidence that more gas is emerging from Arctic soils
as the permafrost melts, and from the seabed where methane has been
trapped as ice for millions of years.
Russian scientists
have reported the discovery of thousands of potential ‘methane-bombs’ –
frozen gas-filled mounds known as pingos – across Siberia, primed to
explode as the ground thaws out.
Swedish scientists
have observed the waters of the Artic oceans ‘fizzing like soda water’
as the ocean currents warm, causing frozen seabed methane to turn back
into gas and erupt.
The essential arithmetic says that so far humans have released about 2
trillion tonnes of carbon, which has warmed the planet by one degree C.
By 2040, we are on track to release another trillion tonnes and push
the planet’s temperature up by 2 degrees or more.
This we can possibly control, by cutting back on our use of fossil
fuels and by ceasing to burn coal. However, there is no way we
can control the methane venting naturally from the seabed and permafrost
once it starts – and there may be 5 trillion tonnes of it. This
phenomenon is known to scientists as the ‘clathrate gun’. If it fires,
the fate of the entire human species is at risk.
Technical difficulty in measuring the Earth’s natural methane
emissions and estimating the size of its reserves has until now led to
the methane threat being discounted, or downplayed, in warnings about
dangerous climate change by the Intergovernmental Panel on Climate
Change and other agencies.
That time is over. We are now receiving early warning of a major
methane release. If it runs out of control, there will be nothing humans
can do to prevent the planet overheating quite rapidly.
This makes it more urgent than ever that governments and corportaions
of the world united to cut human carbon emissions. The recent Climate
Turning Point report says the world has until 2020 – just two and a half
years – to start lowering global carbon emissions by cutting fossil
fuel use. Time is running out – and the methane gun makes matters all
the more urgent.
This means that countries like America and Australia have to cease
their dangerous do-nothing policies and stop mining coal, countries like
India and China need to stop building coal-fired power stations
immediately – and every country needs to make a far larger effort to
scale back its carbon emissions from transport, agriculture and
industry.
Denialists and do-nothings defend fossil fuels on the grounds ‘they
are good for the economy’. They appear not to understand that you first
have to have a human civilization or a human species in order to have an
economy.
That is what is now at stake, if the frozen methane escapes.
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