Back in August 2021 I made a video looking at a new publication from the Intergovernmental Panel
on Climate Change. That report was the first in a series of three and it focused on the physical
science that defines the extent of our current climate emergency. The second of the three reports
has just been published. This one explains the climate impacts on human societies and the natural
world drawing on evidence from more than 14,000 peer-reviewed scientific studies from all over
the planet. And I'm bound to tell you it makes for pretty grim reading. The report finds that
climate change is already killing human beings, destroying nature and making the world poorer.
The meeting of twenty thousand delegates at COP 26 in Glasgow last year completely failed to put
the world on track to reduce greenhouse gas emissions in line with safe levels of warming
and we've now gone past many of the tipping points that scientists have been warning us
about for decades. That means that in many cases the damages we'll see in the coming years will
go beyond levels that humans and nature can adapt to. So are we completely out of time
or is there a glimmer of hope that we can salvage something from the coming wreckage?
Hello and welcome to Just Have a Think. If you've not come across the IPCC before they're the United
Nations climate science body made up of hundreds of the world's top climate scientists. They issue
a set of major assessment reports every few years that review tens of thousands of peer-reviewed
papers to reach consensus on the most up-to-date state of knowledge about climate change.
The fundamental framework for all IPCC reports is risk, because although,
as many sceptics very enthusiastically point out, it's impossible to give absolute cast
iron guarantees of what the climate will be like in 10, 20 or even 80 years time,
it is possible to give a very accurate assessment of the level of impact that climate change
has already had on our planet. And modern science can now provide us with very robust
ranges of projected future outcomes so that policy makers can start to assess the risks and either
make radical changes to avoid those risks or start planning the logistics and contingencies
that they'll need to have in place in the next few years in order to adapt and survive. Which, by the
way, is what COP 26 in Glasgow in November 2021 was all about, and why it was such a disappointing
failure, as I outlined in another video that you can jump back to by clicking up there somewhere.
The IPCC visualizes those risks and their causes and consequences
on a sort of anti-wheel of fortune. At the centre of the wheel are the interconnected variables
of climate hazards, vulnerability and exposure of human systems ecosystems and biodiversity.
They're all interconnected of course, so you get this kind of overlapping Venn diagram of doom.
We've known for decades that human society, especially western human society,
has been releasing increasingly larger amounts of greenhouse gases. Those emissions are causing
changes in our climate and those changes have damaging impacts to humans and to earth's natural
systems. We humans are also directly impacting nature through widespread changes in land use
for things like agriculture, mining and logging, so the ecosystems that human beings and all other
species rely on for survival are getting clobbered from all angles. We're only now
starting to panic a bit and think globally about adaptation. And some of those adaptations may
actually be doing more harm than good, which is why this word maladapts appears in red. More about
that later. Nature is also starting to respond to the change in climate but the climate is now
changing so quickly that losses and damage are inevitable and unavoidable in the coming years.
That is, I think, what you might call a vicious circle. The virtuous circle that the IPCC are
urging us all to move towards as quickly as possible looks more like this. A transition
in human systems will mean that our species will no longer be a net emitter of greenhouse gases.
Our adaptations will be carefully considered and targeted instead of knee-jerk and reactionary.
That'll begin to reduce the damaging impacts on our way of life and on nature's ecosystems. Those
ecosystems will respond by becoming healthier and more sustainable, providing the essential life
support systems for us humans and the millions of other species we share the planet with.
Human development will become climate resilient, focused on human health and well-being as well as
equity and justice. And there will be equal emphasis on ecosystem and planetary health. Now,
listening to that last bit you might think I'm about to break into a rendition of
kumbaya, so let's just bring ourselves back down to earth again and remind ourselves of the size
of the challenge that this latest report sets out. Our lives and livelihoods are dependent on
ecosystems and species that provide people with food and water in different parts of the world.
All of them are being impacted in some way by climate change. Although those impacts
obviously vary from one region to another, as an overall global picture every single sector is now
experiencing a high level of climate impact. And it's not just the warmer mid-latitude regions as
you might think. In fact if you drop down the list it turns out that it's actually Europe and North
America that are the two regions where a high level of impact is affecting all natural systems.
We're already witnessing more and more heat waves, flooding, droughts and wildfires on land plus
extreme hot spots in our oceans. The IPCC tells us that many of those events are resulting in
increasingly irreversible losses. More people are dying as a result and essential forestry land is
being destroyed, not just by fire but by drought as well. Ocean heat is causing coral bleaching
which is destroying reefs and all the rich marine biodiversity that they support.
Marine kelp forests, which pound for pound can capture and store far more carbon dioxide
than land-based forests, are disappearing at an alarming rate. Approximately half of all marine
species assessed globally are now shifting towards the poles to escape the uninhabitable warm waters
at mid-latitudes, and on land a similar proportion of species are moving to higher elevations.
Sea level rise has made hurricanes and tropical cyclones more severe, with all the related losses
and damages that they bring. Hundreds of species have already been pushed to extinction and
thousands more are being brought to the brink all the time as each year goes by. The impacts on the
planet's hydrological systems are approaching irreversibility as a result of retreating
glaciers and changes in mountain and arctic ecosystems driven by permafrost thaw. Since the
last IPCC report in 2014 the data show much more clearly that it's human-induced climate change
that's causing the increases in frequency and severity of all these extreme events, and the
extent and magnitude of climate change impacts are larger than estimated in any previous assessment.
As in previous reports, the IPCC used what they call Shared Socioeconomic Pathways or SSPs
to provide projections for likely future outcomes. These numbers represent Watts per square metre of
average warming across the entire planet, it's what the science pods refer to as radiative
forcing. That radiative forcing currently sits at about 3.2 watts per square metre. If we carry on
as we are we could reach a warming level of 8.5 Watts per square metre by the end of the century,
and in that scenario all of the IPCC's rather diplomatically titled 'reasons for concern' go
pretty much off the charts. Average global temperatures will be up to about 5 degrees
Celsius. Kelp forests, warm water corals, seagrass meadows and salt marshes will almost completely
disappear. Impacts on terrestrial and freshwater systems will be equally catastrophic and global
human death from heat stroke, UV exposure and diseases like malaria, dengue and others
will be out of control. Even if we manage to slow the increase right down and limit ourselves to the
mid-range scenario of SSP-2, the projections still show that we're in pretty big trouble.
The most recent studies show that if global warming exceeds 1.5 degrees
Celsius above pre-industrial levels, even if we only overshoot that limit briefly,
then some of these impacts will themselves cause the release of yet more greenhouse gases,
and some of them will be irreversible, even if we somehow managed to reduce global warming
later on in the century. So, are we likely to exceed 1.5 degrees? Well, we're currently sitting
at 1.2 degrees and global greenhouse gas emissions would have to be halved by 2030 if we're to stand
any chance of avoiding that temperature overshoot. Right now global greenhouse gas emissions are
increasing each year not decreasing. I'll let you come to your own conclusions on that one. So,
this latest IPCC summary places far greater emphasis than previous reports on how we can
fundamentally adapt our societal behaviours and infrastructure to cope with what's coming
our way in the next few decades. Those changes will affect every aspect of human life on earth
from land and ocean ecosystems, with things like improved coastal defences and better management of
coastal ecosystems like mangroves, through to much more environmentally intelligent design
for our urban environments, where two-thirds of the world's population will be living by 2050.
Governments will need to prioritize funding for root and branch improvements to national
and international infrastructure and transition our energy systems away from fossil fuels and
onto renewable technologies. And perhaps most poignantly of all, given the current state of
world affairs, it'll be crucial for world leaders to work hand in hand to ensure peace
and facilitate human mobility. That's not some idealistic hippie aspiration. The fact is that
millions of people are going to be displaced from uninhabitable regions and also as a result
of regional conflicts for increasingly scarce resources. If we fight amongst ourselves then we
can pretty much be assured of mutual destruction sooner or later. But if we find a way to genuinely
work together as an international community then we might just achieve an orderly and planned
relocation and resettlement of what could be as much as a third of our global population.
And along the way we need to ensure we don't make adaptations that cause more harm than good.
That's that maladaptation word that we saw earlier. Since the last IPCC report in 2014
there's increasing evidence that these maladaptive responses are on the increase. They're often
a product of short-term knee-jerk reactions by governments and organizations keen to demonstrate
that they're taking some sort of action against climate change, without the necessary due
diligence and thought about potential longer-term consequences. For example, say the IPCC, while
building a seawall is a great idea for reducing the impacts on a coastal town in the short term,
it might end up locking in increased levels of exposure to climate risks in the long term
if it's not properly integrated into a longer term climate mitigation and development plan.
Equally, measures to achieve fire suppression in naturally fire adapted ecosystems,
while no doubt well-meaning, might turn out to be completely counterproductive by reducing
the space needed for natural processes, which in turn could severely degrade the local ecosystem.
Likewise planting trees, which is very much the on-trend action of choice that many westerners
believe to be the cure-all to save our skins. In some cases it may well be a useful thing to do,
but indiscriminately planting trees wherever there's a bit of available space
could be disastrous. If that patch of land has never had trees on it before
then the chances are it's not well suited for them and the newly planted trees will probably die.
Or they might survive in a region that was previously providing an important level of
reflectiveness or albedo, and once the tree canopies cover over all the ground that albedo is
lost. And of course these sorts of well-meaning developments might also impact negatively
on the lives and livelihoods of already very vulnerable indigenous people who are almost always
the ones who cop for the consequences of policies and actions imposed upon them by us westerners.
There's no suggestion here that initiatives like tree planting
are inherently bad. The point is they need to be thought through extremely carefully
before we go bowling in like a bull in a china shop. What we're after, as this chart shows,
is as high a level of climate resilient development as possible. According to the IPCC
we've already missed a bunch of opportunities as a global community to reach the very highest level,
which they represent with this dotted line. There'll also be climatic and non-climatic
shocks along the way, like the COVID pandemic and of course the current conflict in Ukraine.
Those shocks will put significant wobbles in the development lines.
If we choose to continue with our current levels of consumption and greenhouse gas emissions
then we're on a race to the bottom. But, say the IPCC, if the right cumulative choices and actions
are made by governments, commerce and civil society to engage with adaptation, mitigation
and development actions in areas of policy, economy, ecology, social culture and technology,
then there is still a small window opportunity to drag ourselves back up to a level at which we
can survive and thrive. That window is rapidly narrowing though according to the IPCC report.
Our global carbon budget gives us fewer than eight years of emissions left at current rates.
So, we really have reached the end of the road down which we've been kicking the metaphorical can
for about the last three or four decades or so. Time's up. That's it for this week. As always,
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