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| Credit: NASA |
What does climate change mean for you?
Sorry about the break, I've been rather busy over the past
month, with astronomy summer school and moving to Warwick. Business as usual
will now resume…with any luck.
Yesterday the Intergovernmental Panel on Climate Change
(IPCC) released the first part of their fifth major report, an update on the
current state of our knowledge about climate change and global warming. The
first document, the Summary
for Policymakers, is pretty much what it says on the tin: A brief (35 page)
collection of all of the major points, so that anyone who this concerns can get
a good idea of the facts without having to read the whole report, due out soon,
which I imagine will be rather longer.
And as it really concerns all of is, I had a read of it, so
will talk a little bit about what it says and what I think about it. All the
facts below are from the report unless otherwise linked.
The first point it makes is that warming of the climate on a
global scale is “unequivocal”. We now have consistent data about changes in
clime from the middle of the 19th Century, and very good data from
1950.
This data shows beyond any doubt that the temperature of the
Earth, both land and sea, has increased by 0.65 to 1.06°C from 1880. It shows
that the last three decades were each hotter than any since 1850. By analysing
ice cores and other palaeographic records, the figure can be extended: The last
three decades were the hottest for 1400 years.
That may not seem like a huge temperature rise, but that’s
an average temperature. Shift the average even a small amount, and the extremes
at both ends change. This temperature rise will cause and is causing warmer and
more frequent hot days, more heat waves, worse droughts and increased likelihood
of storms.
More details don’t improve the picture. Glaciers are shrinking
and the Greenland and Antarctic ice caps have been losing mass substantially in
the last coupe of decades. Added to the thermal expansion of the oceans due to
the increased temperature (When you heat water it expands: look closely next
time you boil a kettle to see this), this has lead to global sea level rises of
almost one fifth of a meter over the past 100 years. Not a huge amount, but it’s
still going up and the rate is increasing.
And it really is all our fault. The report states: “It is
extremely likely that human influence has been the dominant cause of the
observed warming since the mid-20th century”. As Sarcastic Rover tweeted, this is “science
talk for YES I’M CERTAIN!” Emissions of greenhouse gases such as carbon dioxide
and methane by humans have, beyond any reasonable doubt, been the main cause of
recent climate change.
This means that predicting how this will carry on depends on
what we do in the future. Unchecked, the temperature will continue to rise by
0.3-0.7 degrees by 2035, and then get hotter. Keeping the rise below 2°C before
2050 will be unlikely. Sea levels are going up almost regardless of what we do,
with a rise of between 1 and 3 meters before 2300.
Some of these changes are unavoidable, but others aren't.
Thomas Stoker, co-chair of the IPCC, put it
simply: To limit climate change “will require substantial and sustained reduction
of greenhouse gas emission.”
Plot from the IPCC report showing the global temperature since 1850. This is plotted as the difference from the average temperature for that whole time period. The increase is can be clearly seen. The top graph shows the average temperature for each year, the bottom the average temperature for each decade.
This means then that any consideration of the future is
almost certainly going to be defined and shaped by climate change. And as that’s
vaguely what this blog is about, I probably should talk about climate change a
bit.
Climate change has been described many
times as our biggest challenge,
the biggest threat to human civilisation facing us in the future. I don’t think
it’s quite as simple as that.
A while ago I read the Rational Optimist by Matt Ridley. I
don’t have it to hand so can’t quote it directly, but he argued that we didn't
need to worry about climate change as it wouldn't affect human civilisation
that much. Coastal areas would be affected and we’d have to adapt to hotter
weather, but no drastic action was needed. I remember disagreeing, but not
being able to fault his logic. Now I've realised that he was right…for some
of us.
I think it’s quite possible that the richer nations in the
world could handle climate change quite easily, for the simple reason that every
year be become less and less connected with the natural world around us. Not in
a spiritual, “connect with nature” sense, but in that we are less reliant on
nature to provide our needs. Half of us live in cities, artificial environments
that provide most of our needs in a way that is very much disconnected form the
world around us. Over the next 50 years this disconnect will only get stronger,
as we increase our ability to grow food in vertical farms, produce artificial meat
and create oil
in labs. Apart from building bigger flood defences, climate change in rich cites
may just result in business as usual.
But that will only protect a tiny fraction of the world. The
vast majority of the world, who don’t live in super high-tech cities and whose
lives are still inextricable tied up in the world around them, will undergo, and
are undergoing, huge suffering. According to Christian
Aid, which is already working in areas affected by climate change across the
world, tens of millions of people will do hungry, hundreds of millions will
have to leave their homes as sea levels rise and billions will suffer water
shortages.
This doesn’t even touch on all of the other life we share
this planet with, which is currently undergoing unprecedented levels of
extinction, also partly our fault.
The great irony of climate change is that the people who
have cause it are mostly safe, whilst those how had nothing to do with the increase
in emissions are the ones who will be most affected.
Instead of “our greatest challenge”, I think climate change contributes
to one side of the coin that sums up our challenge for the future. Very roughly,
I think our challenges can be summed up as a tension between resources and environment.
Resources, because before very long we will have ten billion people on the
planet. And while the small percentage of us living in the most developed countries
could take a hit to the amount of stuff we use, for most of the world the right
way is increased resource use. We should be aiming to move into a world where
everyone has access to food, water, healthcare, education and the chance to
live a fulfilling life. Doing that for ten billion will take a huge increase in
the amount of resources we need.
But these resources come at a cost to the environment.
Digging up the ground for metals, destroying the rainforests to provide land, adapting
vast areas of land for farming at the expense of all of the other land. And of
course, powering this all by burning fossil fuels and causing global climate
change.
The challenge then is this: how do we feed ten billion people
without further damage to the environment.
The IPCC report leaves us in no doubt that human activity
has caused and will continue to cause massive detrimental effects on the environment.
The people living alive today will be just the first to be affected, but we are the people who can do the most to change the future, to avert the worst predictions of climate
change. Even is we feel it doesn't affect us, we have to do it. We have to create
a world where our need for resources is in balance with the environment around
us. We owe it to all the life on this planet, to our children and grandchildren.
And we owe it to the ten billion.
A note on climate scepticism: Much has been made of the “warming
slowdown”, the observation that the average temperature has not increase since
1998. This is answered very simply in the IPCC report. 1998 was a particularly
hot year, so the average since has been affected. 15 years is way too short a
time to say anything meaningful about the climate, as it’s too sensitive to
weather like this. 50 years of no warming would be relevant, 15 years isn't. There
is an easy way to challenge climate change science: gather data and publish in
a respected peer-reviewed journal. A column in a newspaper really doesn’t
count.
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