3°C
It can be the difference between snow and sleet
Wearing a jacket or not
In your day-to-day life, it may not seem significant
But 3°C of global warming would be catastrophic
Heatwaves, droughts, extreme precipitation, even fire
3°C of warming is really disastrous
The scary thing is, the world is well on its way there
Since the industrial revolution, the Earth has warmed between 1.1°C and 1.3°C
This is a problem that babies you pass in the street will have to live with
Children born today...
...are up to seven times more likely to face extreme weather than their grandparents
If global temperatures do rise by 3°C...
...what would their world look like?
Rising sea levels
Desertification
Hollywood has always enjoyed imagining the end of the world
While blockbusters like this are clearly fiction...
...this film will show the scenario we all face...
...unless more drastic measures are taken to stop burning fossil fuels
In some parts of the world the effects of inaction are already clear
The slums of Bangladesh’s capital are filling up with climate migrants
Minara comes from Bhola District, an area in southern Bangladesh
There, like many other parts of the country...
...rivers swollen by heavier rain and melting Himalayan glaciers...
...are washing away people’s homes
Many, like her, have lost everything
Our home in Bhola had endless amounts of land
There was lots of space for farming, we had a spacious house
There were different types of fruits, vegetation and trees growing at home
We used to eat the fruit from our own trees
I can’t eat them now because they don't exist anymore
Since the river flooded for the third time, I had to flee to Dhaka
Life was much better back home
It was unbearable to live through, truly intolerable
We didn’t have the time to save anything at all
1.1°C to 1.3°C of global warming has already transformed Minara’s life
It’s one of the reasons why so many migrants like her...
...are moving to the city each year...
...nearly 400,000 according to the last estimate
And climate models show there could be much worse to come
Climate scientist Joeri Rogelj...
...has spent the last ten years modelling future climate scenarios...
...for the United Nations
The models we use to carry out this exercise...
...really represent the state of the art...
...of our current knowledge of climate change and where we are heading
Joeri’s projections use data collected by hundreds of scientists around the world
Here this is the 3°C level...
...and so there is at least a one-in-four chance that under current policies...
...we would hit 3°C by the end of the century
This is just one of the scenarios Joeri looks at
Another one imagines that all policy promises are kept
The most optimistic assumes that all promises have been kept...
...and net-zero targets are met
Where our best estimate ends up around 2°C at the end of the century...
...there is still a one-in-20 chance that we end up with 3°C instead
One would not be entering a plane if there is a one-in-20 chance...
...that the plane will crash
A rise of 3°C would affect everyone
Even wealthy cities in rich countries wouldn’t be immune to the consequences
European capitals like Paris and Berlin...
...would bake under more extreme heatwaves
Frequent storm-surges in New York could turn parts of the city desolate
In many ways, cities magnify, intensify climate events
Cities are hotter than the places around them...
...they tend to be more vulnerable to flooding
And you can get a really bad event in a city in a way that you can’t in the countryside
And because of their denser populations...
...disasters in a city affect far more people
Some cities might be badly prepared for the changes coming
But they have the means to adapt
Cities tend to be wealthier than surrounding places
They have a lot of amenities
A city that has taken seriously the risks of a 3°C world...
…wouldn’t necessarily be a worse place to be in a 3°C world
But a city that hasn’t prepared for these sort of eventualities...
...that might be a really nasty place
So far, many developed cities have got off lightly...
...but some rural parts of the world are suffering disproportionately
Smallholders—small-scale farmers—are particularly vulnerable to climate change
And there are over 600 million around the world
Smallholders with farms under two hectares...
...produce around a third of the global food supply
Central America’s “Dry Corridor”...
...supports a mix of smallholdings and medium-sized farms
Sandwiched between the Pacific Ocean and the Caribbean Sea...
...the area is prone to droughts
Israel Ramírez Rivera is a smallholder in Guatemala
Here, climate change is making the dry seasons longer, and more severe
This is the biggest ear of maize that this plot could deliver
He depends on his crops of corn and beans
But they’re getting harder to grow
The surrounding mountains...
...used to provide us with native food...
...and now that isn’t an option anymore...
...due to climate change and its effects
Nearly two-thirds of the smallholders in the Dry Corridor now live in poverty
The impact of all of this for us...
...malnutrition among children
We’ve lost a few
For my crops especially, the midsummer heat is harder than before
The plant dries up and can’t provide us...
...with the necessary food provision
Severe droughts in Central America...
...are now four times more likely than they were last century
Many families from here have gone to the States
The economic despair and debts...
...have pushed many people from this community to do this journey
Migration from Guatemala to the United States has quadrupled since 1990
Not all of this has been due to climate change
But longer droughts would force even more to move
In a 3°C world, annual rainfall in this region...
...could drop by up to 14%
At 3°C, over a quarter of the world’s population...
...could endure extreme droughts for at least a month of the year
Northern Africa could see droughts that last for years at a time
But for some, too much water will be the problem
10% of the world’s population lives on a coastline...
...that’s less than 10 metres above sea level
For these coastal inhabitants, a 3°C world would spell disaster
By 2100, global sea levels could have climbed by half a metre from 2005 levels
Low-lying cities like Lagos would be especially vulnerable...
...with up to up to a third of the population displaced
And in Fiji, rising waters are already upending lives
You can see the graveyard there, it’s all under water now...
...due to this rising sea level and climate change
The village of Togoru in Fiji is being swallowed by the sea
Barney Dunn, the village headman, has seen over half the village disappear
Relatives’ houses have been abandoned, and family graves are now under water
We have been asked by the government to relocate...
...but no one wants to relocate...
...because we have our great-great-grandparents down there in the sea
This is the place we’ve been brought up in
...it’s not easy to leave
Past attempts to build a seawall haven’t worked
But Barney sees building a new one as the village’s only hope
If they do that, maybe we can save whatever is left
But if we don’t have the seawall, then it will be keep eroding and time will come...
...maybe in ten,15 years, Togoru will be all eroded
Rising seas also mean storms cause more floods
And many more countries could suffer
The Philippines and Myanmar are just two countries...
...that will also see an increase in storm surges in a 3°C world
To escape, many will move…
…often, to urban areas
Half the world’s population already lives in cities...
...almost a third in slums
For them, a 3°C world could be deadly
Minara has moved to Dhaka to escape the impact of climate change
But life could get even worse for her
I’m struggling a lot nowadays
The heat during the day is unbearable
Even late at night it doesn’t cool down
The heat is getting more intense every day
I mean, it’s going to get much worse
I can barely survive it now, how will I live through it in the future?
Dhaka is getting hotter
In the last 20 years the average daytime temperature...
...has crept up by nearly half a degree
Days that approach 40°C are now being reported
And high so-called wet-bulb temperatures are on the rise
A wet-bulb temperature is a measure of heat and humidity
Humans cool themselves by sweating…
But in these conditions, when relative humidity is near 100%...
...sweat doesn’t evaporate well
So people can’t cool down…
...even if given unlimited shade and water
At a high wet-bulb temperature, the body can’t lose heat...
...and so it gets hotter and hotter...
...and the body is designed to work at a given temperature
And if it gets too hot inside, you will die
The human limit for wet-bulb temperatures is 35°C...
...around skin temperature
Dhaka will have a much higher chance...
...of reaching dangerous wet-bulb temperatures...
...if global warming reaches 3°C
You can’t really adapt to that
You have to get out. If the temperature is so high that you can’t work...
...can’t do hard manual labour outside for significant parts of the year...
...then many places will become functionally no longer part of the economy
Jacobabad in Pakistan, and Ras al Khaimah, in the United Arab Emirates...
...have already recorded deadly wet-bulb temperatures
More of the tropics and the Persian Gulf...
...as well as parts of Mexico and the south-eastern United States...
...could all get to this threshold by the end of the century
Climate modelling might show us the weather
But it doesn’t show us its other effects on society
Established migration patterns could change
Climate disasters may exacerbate reasons people cross borders
Within countries, more people will move to cities
In a 3°C world, tens of millions of people a year...
...could be displaced by disasters made worse by climate change
When people are displaced by climate...
…they may well go to cities...
...because cities are the places that attract people from the countryside already
A lot of people who can get to the developed world...
...not least because the developed world tends to be less hot, will give that a go
As migration around the world increases...
...there could be more competition for fewer resources
Water—already a highly contested resource—will be a focal point
Turkey’s new Ilisu dam has reduced the flow of water into Iraq
China lays claim to rivers vital to India and Pakistan
The prospect of a water-conflict makes people very uneasy
How national tensions would exacerbate those sorts of reactions...
...in a 3°C world...
...is the sort of thing that no one should really want to find out
I think you’d have to be incredibly sanguine...
...not to think that the sort of climate extremes that we talk about...
...in a 3°C world wouldn’t lead some places...
...to the brink of societal collapse
Those lucky enough to escape unrest...
...would still have to adapt to a radically different world
People can adapt to climate change in all sorts of ways, one of the most obvious ones...
...is air conditioning
But other ways to adapt at a local or regional level...
...I mean, one of the most obvious is diversifying agriculture
There are physical things you can do, like seawalls
The fact that people can adapt and that adaptation will reduce suffering...
...doesn’t mean that it will eliminate suffering
Suffering is built into this whole process of heating up the planet
Adaptation will only get the world so far
The best way to deal with a 3°C world...
...is not to go to a 3°C world
And that’s why increasing efforts on mitigation are important
It’s why working towards negative emissions...
...that could bring down the temperature after it peaks are important
Once you get to a 3°C world, you are in real bad global trouble
The scale of change needed...
...and the slow progress of governments so far...
...means 3°C of warming is uncomfortably likely unless more is done
Despite existing pledges, greenhouse-gas emissions...
...are still set to rise by 16% from 2010 levels by 2030
The need to act has never been clearer
There’s still time to reduce emissions, so that a 3°C world remains fiction...
...rather than becoming fact
Thanks for watching
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