“When the water came, they did not have a chance.” The inhabitants of the German city of Sinzig were in shock on July 15, 2021. The night before, huge bodies of water had taken over the city, crushed everything in its path and, among other things, killed twelve residents of a home for the disabled.
At the highest point, the water was seven meters above its normal level. The floods came after a massive rainstorm and hundreds of people across Europe were killed.
Less than two weeks later, an army of scientists had gathered for an epoch-making final sprint. In an almost infinite number of video meetings, they put the finishing touches on a massive climate report – a report which, for the first time, unequivocally states that we ourselves are to blame for tragedies such as the one in Sinzig.
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We have involuntarily given a helping hand to floods, hurricanes and forest fires, and disasters will increase in the future. Climate scientists have issued similar warnings before, but the new report is still different.
The report, which comes from the UN Climate Panel, is not only full of insights that no one knew about just a couple of years ago – it also comes at a crucial time. According to researchers, the earth is currently balancing on the brink of an abyss. Our actions have already started at least one catastrophic development, which can now no longer be stopped and more will soon follow.
Fortunately, the report has a solution – a drastic intervention that will save hundreds of millions of people from being driven from their homes.
We can not avoid it
The new the report is the first of three sub-reports from the UN’s climate panel, the IPCC, which deal with climate change, the consequences of climate change for humans and nature, and strategies for reducing greenhouse gas emissions. Together, the three sub-reports will constitute the panel’s sixth major climate report.
Even when the IPCC published its first report in 1990, researchers were relatively certain that there was a link between our greenhouse gas emissions and the rising global temperature. Then the results came as a shock and governments around the world soon agreed that emissions must be reduced. Since 1990, annual emissions have increased by about 60 percent.
A series of IPCC reports followed in the following decades, and each of them stated that we were undoubtedly in the process of changing the climate for the worse.
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Several political agreements have tried to tackle climate change – most have failed. One of the most recent major agreements came in Paris in 2015, when the goal was to keep global temperature rise below 1.5 degrees by 2100. The IPCC’s sixth report highlights our chances of achieving the Paris Agreement’s goal.
“We will see a 1.5 degree increase in temperature over the next 20 years,” says climate researcher Anna Amelia Sörensson, who was one of the leading researchers among the 234 researchers who prepared the report.
“We can not avoid it. At 1.5 degrees, the extreme weather phenomena will be worse than now, but we can not do anything about it. It will happen. Still we must reduce emissions, because with two degrees warming it will be even worse . “
The new predictions about the future climate are in many ways frightening. But they are better substantiated than any previous predictions. And the reason is largely that researchers have eliminated one last consuming uncertainty.
Sensitive climate
Climate scientists have known for decades that greenhouse gases were the culprit behind it Global warming. But they have not been able to establish the so-called climate sensitivity – a measure of exactly how much heating a certain increase in the amount of greenhouse gases provides.
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“This is an extremely important goal and it has been difficult for climate scientists to call in,” explains Trude Storelvmo, one of the IPCC’s leading experts. “We have had a frustrating uncertainty. So even if we knew exactly how big the emissions would be, we would still have great uncertainty about future warming.”
That uncertainty has now been largely eliminated thanks to more measurements of today’s climate, new discoveries about previous climates and more advanced climate models – and this has enormous significance for the entire climate science.
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Greater security of climate sensitivity means that all doubts about the role of humans in global warming have been completely eradicated. Of 1.09 degrees warming, we are behind 1.07 degrees – thanks to emissions that have led to the highest level of carbon dioxide in the atmosphere in at least two million years. At the same time, predictions about future warming have become far more accurate.
In total, science has taken a huge step forward since the IPCC’s latest report from 2013. And the result is not only that we have a more solid foundation to stand on when we have to make decisions about, for example, greenhouse gas emissions. Scientific progress can also have legal consequences in the event of tragedies such as the one in the German city of Sinzig.
The culprit is revealed
Several cities in Europe were laid in ruins in July 2021, and about 250 people lost their lives. The material overheads will probably exceed SEK 80 billion. The reason was huge amounts of rain. In some areas, it rained as much in two days as it normally does in two months.
That same summer, areas in the United States, Canada and Europe experienced record high temperatures. Finland had the warmest month ever measured, and a brutal heat wave ravaged Canada, where the temperature reached as high as 50 degrees – the highest ever measured in the country. The extreme heat resulted in more than 500 deaths and catastrophic forest fires.
The IPCC’s new report leaves no doubt as to where the blame for this type of disaster should be placed.
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“In the previous report, it was clear that global climate change is caused by human activities. In that report, however, it was not possible to determine whether an individual extreme event had been caused by climate change or not, but we can now,” says Anna Amelia Sörensson.
With new advanced climate models, researchers can test how likely a concrete weather event is in reality compared to a world where humans have not emitted greenhouse gases. A study showed that our emissions made the violent European rainstorm 1.2-9 times more likely. Another study revealed that we increased the risk of the Canadian heat wave no less than 150 times.
For the first time, researchers can thus see a solid causal link between emissions and the individual tragedies.
“That connection serves as evidence in potential prosecutions against governments,” says Anna Amelia Sörensson, who believes that this particular scientific advance is putting massive pressure on decision-makers.
Governments that do not take the problem seriously can now be held accountable for their actions. And it could be an important tool, because according to the report, disasters in Europe and Canada are just the beginning.
Disasters are in line
The report presents specific scenarios for climate development during the 2000s, depending on how much greenhouse gas we emit into the atmosphere. If we continue to emit approximately at the level of today’s emissions, we will reach two degrees of warming sometime between 2041 and 2060, and almost three degrees at the end of this century.
At just two degrees warming, violent rainstorms will occur almost twice as often as before global warming, and they will supply an average of 14 percent more water. At the same time, extreme heat will occur six times more often than before and be on average 2.6 degrees warmer.
If we instead increase our emissions, we can at the end of the century have temperatures that are up to five degrees above today’s temperature, and in that case the disasters become even more common and more intense. At four degrees warming, for example, we get ten times more heat waves than before industrialization and they will be on average 5.1 degrees warmer.
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The positive message in the report is that during this century we can reverse the trend in extreme weather phenomena if we reduce our emissions immediately.
On the other hand, we are not so lucky with the rising water level of the sea.
The heat causes the sea to expand and the earth’s melting ice sheets contribute at the same time with large amounts of extra water. Therefore, the sea is currently rising faster than it has in at least 3000 years, and during the years 2006-2015 the water level rose 2.5 times faster than during the period 1901-1990.
The new report makes it clear that global warming will rise in the sea for centuries and perhaps even millennia, even if we stop our greenhouse gas emissions immediately and stabilize the temperature at sea level.
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The long-term rise in sea level is mainly due to the oceans and ice sheets reacting relatively slowly to temperature changes. And even if we keep the temperature increases below two degrees, in 2300 our successors risk a rise in sea level of up to three meters.
Rising sea levels and extreme weather incidents will have consequences that will be felt by the entire earth’s population.
Agriculture will suffer from floods and droughts – with an increased risk of famine in several areas of the world. And hundreds of millions could become homeless as a result of forest fires and floods.
Time has given reports right
Sea levels will rise significantly no matter what we do. But our actions can greatly affect the extent of the increase, the report states.
An effective reduction of greenhouse gases can thus keep us at a three meter high increase until the year 2300, which is significantly better than the increase of up to seven meters, which we get if we instead increase our emissions.
A quick effort can also help with the heat. Although we can now not avoid rising above 1.5 degrees in the middle of this century, we can still manage to bring the temperature to fall below that limit again before the end of the century.
“We can still manage to limit warming. That is the report’s most important message,” according to climate researcher Anna Amelia Sörensson.
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In order to force global warming back below 1.5 degrees in 2100, we must, according to the report, at least halve our annual emissions before 2050, reduce them to nothing around 2075 and then remove all carbon dioxide from the atmosphere.
It is a rock-hard plan, which will require a massive effort. But is there any reason at all to believe that climate models will hold? The climate is extremely complex and the models are only an estimate, so a certain amount of skepticism is in place. Still, the answer is yes, and it only takes a look at what the IPCC’s old reports have said about the climate to this day.
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All IPCC reports have been met with harsh criticism from people who believe that researchers are exaggerating the problem. And in some cases, the old forecasts have shot over targets. The first report from 1990, for example, ended up 17 percent too high when it predicted the development of temperature until 2016.
But researchers’ models have just as often ended up too low. The forecasts of the temperature in the IPCC’s second and third reports ended up being 28 and 14 percent too low in relation to reality, respectively.
When the forecasts have not followed the actual development down to the smallest detail, it is mainly due to doubts about the so-called climate sensitivity – a doubt that has now been significantly reduced – and uncertainty about future greenhouse gas emissions.
In any case, the researchers have been honest about the uncertainties. And on the whole, the IPCC’s climate models have come incredibly close to real developments, both in terms of temperatures and rising sea levels.
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Researchers are still honest about the uncertainties, but they have every reason to believe that the new climate models are even more accurate than the old ones.
“Enormous progress has been made since the first report,” says Trude Storelvmo.
“The main message has not changed, but we have become much more confident in our cause.”
Despite the progress, there is still some uncertainty in the new report, which may prove to be of great importance. Researchers have revealed several phenomena that could potentially trigger violent chain reactions – for example, a collapse of the ice sheets and extensive forest deaths as a result of the warming.
These phenomena are unpredictable even with the researchers’ latest knowledge and even if they are unlikely, they are far from impossible – especially with large greenhouse gas emissions. If they do, the IPCC’s current forecasts may turn out to be completely incorrect; a collapse of the ice sheets can, for example, cause the sea to rise by more than 15 meters.
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