The climate’s response to energy changes takes decades
- 16 Feb 2012, 18:05
- Verity Payne
If the world switched from coal-fired power to low-carbon energy
there would still be a hiatus of around fifty years before
greenhouse gas emissions reduced and temperature stabilised,
new research. What's more, switching to natural gas is unlikely
to benefit climate over the coming century.
Researchers Nathan Myhrvold, of Intellectual Ventures, and Ken
Caldeira of the Carnegie Institution for Science, used basic
mathematical models to calculate how much greenhouse gas emissions
and global average temperature might change over the coming century
if we switch to low-carbon power sources. The green energy measures
considered are hydroelectricity, solar, nuclear, wind, natural gas,
conserving energy where possible, and carbon capture and
The research, published today in the journal Environmental
Research Letters, suggests that a transition to low carbon
energy will initially cause greenhouse gas emissions to rise
compared to coal power. This is because setting up the green power
plants will result in greater greenhouse gas emissions than using
existing coal-fired plants.
With new green power plants under construction - which would
increase emissions in itself - we would also continue to use coal
energy, thus adding to existing emissions. Once up and running,
however, the green energy plants emit far fewer greenhouse
"You have to use the energy system of
today to build the new-and-improved energy system of tomorrow, and
unfortunately that means creating more emission in the near-term
than we would otherwise. So we incur a kind of 'emissions debt' in
making the transition to a better system, and it can take decades
to pay that off. Meanwhile, the temperature keeps rising."
The delay in climate benefits of green energy would also be
compounded by the 'thermal inertia' of the oceans - which means the
oceans take a while to release any heat they contain.
The research hasn't yet received much media coverage, apart from
in the Mail Online, which rather predictably misinterprets the
paper with the headline:
Switch to low-carbon power sources 'risks making global warming
worse' study warns.
In fact in the long term - after around four decades for
solar wind and nuclear power - low-carbon energy sources will
reduce global warming.
Switching to natural gas won't benefit climate this
The researchers also found that switching to natural gas simply
delays inevitable warming. They write:
"Conservation, wind, solar, nuclear
power, and possibly carbon capture and storage appear to be able to
achieve substantial climate beneﬁts in the second half of this
century; however, natural gas cannot."
So although natural gas is often touted as the best way to
bridge the transition to low carbon energy it is not likely to
achieve greenhouse gas and temperature reductions this century.
Delaying switch to green energy 'risks even greater
The researchers warn that we should switch to low-carbon energy
sources sooner rather than later. They write in the research
"... Delaying rollouts of
low-carbon-emission energy technologies risks even greater
environmental harm in the second half of this century and
As Caldeira puts it:
"There is no quick fix to global
warming. Shifting from one energy system to another is hard work
and a slow process. Plus, it takes several decades for the climate
system to fully respond to reductions in emissions. If we expect to
see substantial benefits in the second half of this century, we had
better get started now."