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The climate crisis: Why 1.5 degree of warming fails to capture our current mess
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The climate crisis: Why 1.5 degree of warming fails to capture our current mess

Fires rage in the forests of northern Morocco in August 2021.


Alok Sharma, COP26’s president, said that the conference was a result of almost 200 countries. adopting the Glasgow PactThe world had kept 1.5 degrees within reach, but notedIts “pulse” is weak.

Scientists warn that if the temperature rises above this level, there is a high chance that many will suffer. The Arctic ice sheets could disappear, and island nations could end up under water. developing countries, already besieged by climate changeExtreme weather events are more likely to occur in areas that are more vulnerable. Bushfires will burn more intensely, the oceans will become acidic, and hurricanes are more likely to wreak havoc on cities.  

Since the 2015 Paris Agreement was adopted, but earlier this calendar year, the world has been working hard to keep the global temperature rising below 1.5 degrees Celsius. the latest IPCC report on the physical science basis of climate changeThose aspirations were severely damaged by this event. Climate scientists believe that, based on current trends, we are very likely to exceed 1.5 degrees Celsius of temperature warming. There is only a small window of opportunity to reach this goal.

Projections support this. The International Energy Agency (IAEA) announced that if nations meet their pledges “in whole and on-time”, we might limit the rise in global temperature to 1.8 degrees Celsius (3.2 degrees Fahrenheit). A week later, Climate Action Tracker suggested that meeting those same pledges put the planet on course for a rise of 2.4 degrees Celsius (4.3 degrees Fahrenheit). 

Although these temperature increases have been the subject of climate discussions for years, they do not reveal the full impact that humans are having. The planet doesn’t heat up evenly. The climate system governs and is governed through a complex series of interactions among seas and skies and forests and deserts, oceans, ice caps, and oceans.

Humans are creating unbalanced systems by burning fossil fuels and releasing greenhouse gases. This can lead to unpredictable changes. Already, the Earth has warmed by 1.1 degrees Celsius. We are already seeing some of these changes today.

How much will the temperature rise by the end the century? In some ways, that’s a misleading question. Instead, we need instead to focus on the large, often unanticipated impacts that these increases will have upon the planet.

Fires rage in the forests of northern Morocco in August 2021.

On August 15, 2021, fires erupted in northern Morocco’s forests.

Fadel Senna/AFP/Getty images

Global average temperature

Two critical temperature thresholds are what you will always hear about when it comes down to limiting global warming.

These numbers refers to increases in the global mean temperature — the average temperature across the globe. Since generations, scientists have known greenhouse gases, and in particular carbon dioxide, play a crucial role in warming the planet. This fact was noticed by Svante Arrhenius, a Swedish scientist. 

Our understanding of this relationship has only grown since Arrhenius. For example, scientists can drill into thick ice and retrieve rod-like coresThese serve as planetary timestamps. Cores from Antarctica have shown that global mean temperature levels are in line with carbon dioxide levels. This is true even back to 800,000 years ago. 

Global mean temperatures are not a reliable instrument. This is not necessarily a bad instrument. It’s useful to project how much global average temperature will rise based on the amount of carbon dioxide we put into the atmosphere. 


Trends in global mean temperature between 1990 and 2020 in degrees Fahrenheit per decade.

Climate Action Tracker and the IEA examine the amount of carbon dioxide that is expected to enter our atmosphere based upon pledges to reduce emissions. They then use relatively simple calculations in order to calculate how much temperature rises if pledges are fulfilled. 

These calculations are not enough. I might not notice the temperature difference between 1.5 and 2 degrees Celsius if I raise the thermostat in my apartment by 1.5 degrees. This binary view of the planet misses a lot of the story. 

Andy Pitman is the director of the ARC Centre of Excellence for Climate Extremes Australia. “There’s no nuance to the conversations.”

Global mean temperatures benchmarks are useful because they set targets that can be met. It is important to understand how different levels of warming could increase the likelihood for heatwaves, decrease Arctic ice cover, or reorganize ocean ecosystems around the world. 

You will need to have extremely complex climate models in order to do this. 

Physics laws

Pitman claims climate models work because they follow the laws of nature.

Pitman states, “If astronomy is believed to work, your microwave works, and an ultrasound works,” Pitman adds, “if these things work, they are because of laws of physics.”

“It’s these laws of physics that are built into our climate models to make predictions.”

Climate models have been around since the 1960s, and despite what you might read on the internet to the contrary, they’ve been around for a long time. fairly good at predicting some of the ways the climate will changeDue to rising greenhouse gas emissions. “Even those primitive models from the ’60s have basic projections that have held up in time,” Matt England, an oceanographer with the University of New South Wales Climate Change Research Centre, says.

The models’ complexity and resolution have increased tremendously over the past 60-years. Numerous models provide different projections of different climate phenomena. 

Some climate variables correlate well with rising global mean temperatures. For example, certain temperatures will cause ice sheets to melt and sea levels to rise. In practice, scientists are unable to plug 1.5 degrees Celsius of warming into a digital Earth and see the entire planet the computer generates. To simulate such a world, you’d need an incomprehensible amount of computing power. Pitman emphasizes that these climate models are independent of models used by Climate Action Tracker or the IEA to project how much the world would warm on average. 

Climate scientists use many different models to predict climate changes that could occur at higher temperatures. They’re not perfect, and there’s some uncertainty. “There’s always going a little uncertainty because different models simulate different climates,” Sarah Perkins Kirkpatrick (climate scientist at UNSW Canberra) says.

Perkins-Kirkpatrick is an example of a heat wave researcher. She studies how warming of 1.5 to 2 degrees Celsius, or more, might affect the frequency and intensity. The models show that lower temperatures are worse, but the uncertainty grows as temperatures rise. 

This doesn’t mean things will get better. However, it is still unclear how much worse they will get. 

Although it is difficult to predict how 2 or 3-degree Celsius warming will affect smaller scales, science is still in its infancy. It is hard to predict how weather patterns, ocean currents, land and other factors will change and what feedback loops will result. Pitman claims that there is no correlation between the global mean temperature increase and the impact of extreme events on a city or region.

This is where the blunt instrument global mean temperature increase fails to convey the urgency and dire situation we are in. 

Too much warming

1.5 degrees Celsius of warming is well-understood science. Climate scientists have studied the impact of 1.5 degrees Celsius warming on different ecosystems, regions, weather patterns, and adaptation. This information is what has been used to create the basis of an IPCC special report published back in 2018

The outlook in that report is dire. It has been three years since its publication. Even in the midst of a global pandemic we have continued to burn fossil fuels, and continue to pump carbon dioxide into our atmosphere at an alarming pace. 

England states, “I think it is pretty much agreed across scientific community that avoiding 1.5 degree Celsius is practically impossible now.”

China, India, the US, and the EU have all pledged to reduce their emissions in the lead-up and during COP26. Climate policy scientists made their suggestions in Science, Nov. 5, writing in the journal Science the new pledges showed a “strengthening of ambition through 2030”With a “stronger near term foundation to deliver on long-term goals of Paris Agreement.” 

This analysis depends on the latest pledges being kept on time and in full. This is not a given. England says that the uncertainty about the future of the planet rests on where humanity will emit its greenhouse gases. 

A glacier collapses into the ocean north of Svalbard, Norway, in Sept. 2021.

In September 2021, a glacier in Norway collapses into the ocean north Svalbard.

Olivier Morin/Getty

The idea that we might still limit global warming to 1.8 degrees Celsius was viewed optimistically in the first week at COP26. A week later, 2.4 degree Celsius of warming was called “catastrophic” 

The sad truth is that limiting the temperature rise to 1.5 degrees per year is too much warming. This doesn’t mean that we shouldn’t do all we can to limit warming below 1.5 degrees. But we need to be realistic. This is not a reason to give in. It actually provides more incentive to decarbonize quickly — the alternative is much worse. Perkins Kirkpatrick claims that 2 degrees Celsius will soon be impossible. 

These numbers indicate more than summers becoming slightly warmer in San Francisco or Sydney. The planet’s response to these changes will vary across its oceans and ice, as well as on land. These numbers could indicate irreversible changes in Earth’s climate. These are the predictions of climate models. 

What amount of warming can we expect by the end century? How much will the temperature rise?

No matter the number, it is already too much.


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