This number is pretty insignificant on its own and doesn’t seem like it could do much harm. But it will change every aspect of our lives.
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People cover their faces in Batemans Bay, NSW on New Year’s Eve last year. Picture: Mark Graham/Bloomberg via Getty Images
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On its own, the number two doesn’t seem overly significant or much to worry about, but in the context of degrees, it could change every aspect of life.
Australia has committed to the Paris Agreement target of limiting climate change to 1.5C, but a growing chorus of experts doubt whether that is achievable with current policies.
The reality is that 2C of warming could occur as soon as 2050 - and that’s significant.
“When it sometimes feels like the weather in Melbourne changes by 20C in the space of a day, a few degrees here and there doesn’t sound like much,” says Sophie Lewis, a senior lecturer in science at University of NSW, Canberra.
“But there’s a big difference in terms of weather and climate, and a world that’s 2C warmer will result in impacts on every aspect of life.”
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In a world that’s 2C warmer, an extra 420 million people will be exposed to extreme heatwaves globally and Australia will cop its fair share.
The impacts will be far more serious than feeling uncomfortable and sweaty.
Professor Emeritus Gerard Fitzgerald from the School of Public Health and Social Work at the Queensland University of Technology said the optimal internal temperature for normal bodily function was around 36.8C.
“The human body generates a certain amount of energy in itself and so it needs suitable environments in order to stay in balance,” Prof Fitzgerald said.
“The body cools itself through evaporation of water, via the breath or sweat.”
As temperatures rise, people sweat more to try to cope and this increases the loss of fluids. If they’re not replaced, dehydration is likely.
In a world that’s 2C warmer, more people will be at increased risk of heat stress in the body.
“If you don’t replace fluid, the human body becomes dry and the place that’s seen is in the bloodstream,” Prof Fitzgerald said.
“Blood becomes thicker and is more likely to clot, raising the risk of heart attack and stroke. At the same time, the body tries to retain water by shutting down the kidneys.”
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Generally speaking, younger and fitter people are well-placed to cope and tend to accommodate by staying in cool places, avoiding exertion at the hottest times and staying hydrated.
But for vulnerable populations - the sick, the elderly and children in some cases - it’s harder to cope with extreme heat, Prof Fitzgerald said.
“The consequences can be serious, from renal failure to heart attack or stroke, to death.
“If the body can’t cool itself enough, human systems can be distressed and that’s associated with respiratory problems, cardiovascular disease, heart attacks but also broader things like mental illness.”
If the internal body temperature hits 40C or above, the consequences can be catastrophic.
“Basically, proteins start breaking down and the body begins dying. Cells break apart. It’s extremely serious.”
Australia will need to adopt an approach to extreme heat that’s similar to what public health and safety authorities elsewhere in the world rely on for blizzards.
“Heat is Australia’s most deadly natural hazard right now,” Dr Lewis said. “There’s likely to be significant health impacts in the future.
“With 2C of warming, the ability to go to work or school will be impacted. It seems unlikely to me that we’ll be able to maintain consistent days of work. People will have to have heat-related absences to stay safe.
“We will need to protect the most vulnerable people in our community - old people, children, pregnant women - and we need to design systematic heat policies like reducing heat exposure at work, play or school.”
Non-essential services and businesses could have to close on extreme heat days in the future, along with schools, she said.
Outdoor activities like sport might become too dangerous over long stretches of the year.
“If we hit 2C, we can’t expect to be living the same lives we’re living now. Going on summer holiday in January, even playing cricket on the beach, isn’t realistic,” Dr Lewis said.
Our Environment
The impact of a warmer world is already starkly evident in one of our most beautiful and environmentally significant assets - the Great Barrier Reef.
Dr David Suggett is a coral reef expert at the University of Technology in Sydney and said in a 2C warmer world, reefs would “quite simply cease to look and function as we know them”.
“At least in the tropics. 2C will push corals closer to their thermal limits for survival along with creating more acid and deoxygenated waters,” Dr Suggett said.
Numerous experiments have demonstrated that such conditions drive many coral species into “metabolic decay”, he said.
“This will all be exacerbated by more routine heatwaves that similarly drive mortality of these same corals through rapid mass bleaching,” Dr Suggett said.
“Fundamentally, these changes will collapse the ecosystems that we almost take for granted these days - reefs primarily provide coastal protection and food, as well as cultural heritage. Corals would likely stop growing at a rate needed to build reefs.”
Sarah Perkins-Kirkpatrick, senior lecturer and ARC Future Fellow at the Climate Chance Research Centre at UNSW Sydney, said warm water corals - the Reef - would essentially cease to exist as we know them.
“Already, the Great Barrier Reef has lost as much as 50 per cent of its shallow water corals. It provides habitat for one million species, not to mention its contribution to things like tourism.
“The destruction would occur quickly and long-term recovery is extremely unlikely. All up, 99 per cent of corals would be lost.”
A full melting of the Arctic during summer would occur more often as the world gets warmer, says Dale Dominey-Howes, a professor of science at the University of Sydney and an expert in hazards, disasters and risk.
“Under 1.5C, this occurs once a Century. Under 2C, it’s once every decade. The more ice that melts, the more the sea rises.”
Permafrost, or the permanently frozen ground in the Arctic Circle, is already melting, but the rate of thaw will continually accelerate, he said.
“At 2C, an extra 1.2 million square kilometres of it is likely to thaw at a rapid pace. The more it melts, the greater volume of methane that’s released into the atmosphere - it’s 25 times more potent than carbon dioxide.
“Methane only lasts in the atmosphere for a decade or so, but it’s impact is serious and will accelerate climate change. Thawing permafrost also releases carbon dioxide, it should be said.”
Much like heatwaves over land or in the atmosphere, oceans are also subjected to extended periods of extremely hot conditions.
“The number of marine heatwaves has already doubled since the early 1980s and if the world warms by 2C, this number blows out to 23 times more heatwaves days, it’s been projected,” Dr Perkins-Kirkpatrick said.
Marine heatwaves not only result in massive coral bleaching but also the degradation of other sensitive ecosystems such as kelp forest. They also impact fisheries and therefore the livelihoods of many people.
The world’s rainforests have already faced decades of challenges due to logging.
Those that remain will essentially dry out under a 2C scenario, making them more susceptible to bushfires.
“In a warmer world, forests are more prone to drying - if they’re drier they’re more prone to wildfires, an event they’ve never previously experienced which could result in a shift to a completely different ecosystem,” Dr Perkins-Kirkpatrick said.
“A good example of this are the bushfires that destroyed ancient Tasmanian forests a few years ago. This was under a warming of 1C. Events like this will become more common under 2C.”
On top of that, rainforests are home to almost half of all the world’s plants and animals and warmer conditions put those at significant risk.
“Two degrees will reduce the size of the Amazon by 40 per cent within 100 years,” Dr Perkins-Kirkpatrick said.
In Australia, a 2C warmer scenario will see more disasters like what we’ve just witnessed over summer, Professor Robert Hill, director of the Environment Institute at the University of Adelaide, believes.
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| NASA Earth Observatory map shows active fire detections in South America, including Brazil, Bolivia, Peru, Paraguay, Ecuador, Uruguay and northern Argentina last year. Source:AFP |
A devastating illustration of this sits in his own background.
More than half of Kangaroo Island was devastated during the worst of the bushfires crisis in January, causing widespread destruction across the pristine and critical environment.
“I’m hearing from people on the ground that’s what happened is the loss of potential regeneration in some areas,” Prof Hill said.
“There are pictures of green sprouts coming out of the burnt landscape, but it’s on the wet margins where there’s water available and the fire wasn’t quite so bad.
“There are big swathes of Flinders Chase where it appears the fire has burnt right down to the mineral soil, smouldering stumps of trees until they’ve killed the tree.”
Fires as intense as what was witnessed in January are rare, but will become more common in a world that’s 2C warmer, he said.
The potential consequences of that is the loss of entire plant and tree species.
“We may have already done so - we won’t know for a while.”
It’s not just the natural landscape that will suffer in a warmer world, but also agricultural and farming land.
There’s evidence that the loss of viable land is already occurring in South Australia, Professor Hill said.
“We have this thing in South Australia called Goyder’s Line and it was mapped a long time ago by someone who understood vegetation very well, who basically drew a line and said, ‘anything south, good for growing crops, north of this line, forget it’.
“He proved to be astonishingly accurate and there were many failed attempts to crop north of the line. There are many abandoned buildings up there to show for it.
“Goyder’s Line is moving south. In some parts of South Australia, it’s moving quite quickly.
“Of course, you don’t have to push south for too long and you run out of land. That’s not something that will happen in a decade, but in some parts of the southeast, the line movement is being measured in kilometres, not metres.
“That’s an example of plants, in this case crop plants, being under pressure from climate change.
Our Wildlife
There’s virtually no doubt that Earth is now within its six mass extinction event, according to Professor Corey Bradshaw, global ecologist at Flinders University.
All species are connected and “this great big ecosystem is constantly interacting”, and so the cascade effects of extinction are serious and dramatic.
“If the predator doesn’t have food, they’re also dying out,” Prof Bradshaw said. “Because of that we’re underestimating the extinction rate from climate change by up to 10 times.”
Under a 2C warmer world, we’re looking at a 10 to 20 per cent extinction rate by the end of the century, just from climate change alone and no other factors.
If you take into account the cascade effects, we’re looking at extinction rates up to 60, 70 and even 80 per cent, Prof Bradshaw said.
Already we’re seeing female sea turtles outnumber males 100 to 1 because the temperature of the sand determines their sex. The hotter the sand, the more likely turtles will hatch as females.
“That will impact the success of their breeding,” says nature campaigner with the Australian Conservation Foundation, Jess Abrahams.
Fruit bats already fall out of trees at 42C - days that will be more likely and more frequent in the future.
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| A flying fox being cared for at Flying Fox Rescue and Rehab. Source: News Regional Media |
In rainforests, animals are already having to migrate to higher ground because of hot conditions, narrowing their habitat reach.
Even our domesticated species are in decline — some 10 per cent of domesticated breeds of mammals have become extinct in human history, with more than 1000 others threatened with extinction.
“All this means that we are now without a doubt well within a sixth mass extinction event,” Prof Bradshaw says.
Our Cities
Already suburbs or communities further away from the coast are hotter than places on the coast.
That’s just part of the climate, but throw in cleared land, inappropriately designed houses with darkened roofs, suburbs with lots of bitumen, no trees and buildings placed close together, and you have the recipe for hotter areas.
That is exacerbating worse consequences of climate change and the extreme temperatures it brings, Dr Perkins-Kirkpatrick said.
“What we’re describing here is the urban heat island effect,” she said. “And many new suburbs amplify increases in temperature because of their design.”
Under 2C warming, Australia will experience four more heatwaves per year, on average, compared to a world without climate change.
In places like India, roads already melt under heatwaves. The tar already goes soft under your feet in Australia, so the design of hard urban surfaces will need to change.
Temperatures that cause road melting are more likely in Australia under 2C warming.
Because roads are black they absorb more heat so they’re much hotter than the actual reading on a thermometer.
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| A 2C rise in temperature would bring with it a higher number of extreme heat days. Picture: Liam Driver Source: News Corp Australia |
Train tracks can also buckle in extreme temperature conditions - it happened in Melbourne in 2019.
That sort of disruption will occur more often. Trains already have to go slower on heatwave days in case tracks in front of them have already buckled.
In 2018, planes were grounded in Phoenix, Arizona in the United States when temperatures reached 49C because of how higher temperatures affect the ability to take off.
“That might be something we need to consider when the world climbs towards 2C warmer,” Dr Perkins-Kirkpatrick said.
Professor Elizabeth Mossop, landscape architect at UTS, said there’s going to be a lot more heat and a lot more heat stress.
“This is incredibly dangerous, especially for vulnerable properties,” Professor Mossop said.
“We need to rethink where we develop, how we develop. There’s no question we need to make changes to how we design and build communities.”
The recent bushfires crisis gave a brief but stark illustration of what a rapidly warming world could mean for everyday life for millions of people who weren’t directly in the firing line, Dr Lewis said.
“It impacted people’s abilities to go on holidays, to move around, to go to work, to breathe clean air,” Dr Lewis said.
“It’s not to say that every aspect of it was 100 per cent climate change, but it’s an indicator of unprecedented extremes under 1C of warming. If you think about another degree, well, you get the picture.”
It’s not just plants and trees in the bush and forests that will be impacted by warmer temperatures, but also those in city environments.
And they serve a greater purpose than an aesthetic one, Prof Hill said.
Green spaces and tree cover help to shade urban spaces and reduce temperatures, as well as provide fresh air, while science has also demonstrated the mental health benefits of parks.
“The problem is that many of the types of trees we have don’t cope well in extreme heat,” Professor Hill said.
“The heat gets to them and so does the lack of water. Trees try to suck water out of a ground that’s dry and they get into trouble. If you’re living in a place that’s in the mid-40s, the last thing you need is for the trees to start dying.”
A 2C rise in temperature would bring with it a higher number of extreme heat days, modelling has shown.
“We’re already seeing that,” he said. “We had a string of days this summer in Adelaide of 45C or above. That’s well outside anything plants have evolved to cope with.”
Links
- Place in Australia that will become a struggle to live in
- Tim Flannery: People Are Shocked About Climate Change But They Should Be Angry
- Who’s Running Late For The Paris Agreement?
- Can We Quit Coal In Time? IPCC Warns World Has Just 12 Years To Avoid Climate Change Catastrophe
- Why Half A Degree Of Global Warming Is A Big Deal
- New Study Reconciles A Dispute About How Fast Global Warming Will Happen
- This Graphic Explains Why 2 Degrees Of Global Warming Will Be Way Worse Than 1.5
- (AU) Kyoto Credit Use Will Halve Cut To Emissions: Climate Change Authority
- The Sad Truth About Our Boldest Climate Target
- We Really May Have Just 11 Years To Save The Climate
- Paris Agreement Targets Need To Be 5 Times Stronger To Actually Work
- The biggest climate change myths debunked
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