What a year it has been...

The Amazon, the largest tropical rainforest in the world, and the Pantanal, the world's largest wetland, burned day and night, wreaking havoc on some of the planet's most valuable ecosystems.

These fires, fueled by deforestation and global warming, echoed the rise in climate-driven wildfires that engulfed California and Australia.

The world's colder regions have also been sounding the alarm.

Sea ice has been decreasing for decades, and melting has accelerated since the early 2000s. According to the U.K. Parliament's Environmental Audit Committee, the Arctic is "warming twice as fast as the rest of the planet." If collective carbon emissions are not reduced, the Arctic Sea could seasonally be ice-free as soon as the summer of 2050, experts have warned.

Evidently, we are on a troubling trajectory to pass a temperature limit goal, and tomorrow marks a historic point in global efforts to combat climate change, regardless of the results of the U.S. election.

The United States is set to become the only country among almost 200 signatories to withdraw from the 2015 Paris Agreement, the historic accord within the United Nations Framework Convention on Climate Change. Having had to wait 12 months for the withdrawal process to be completed, as of Nov. 4, 2020, the country will no longer have to abide by this deal's obligations.

Trump and timeline of the U.S. exit

"The U.S. is proud of our record as a world leader in reducing all emissions, fostering resilience, growing our economy and ensuring energy for our citizens. Ours is a realistic and pragmatic model," Secretary of State Mike Pompeo had said on Twitter on Nov. 4, 2019, confirming the U.S.’ cessation of all participation in the deal. However, the seeds of this anti-climate stance were planted long ago, even before Donald Trump's presidency.

Trump's most notable tweet on the matter came in 2012 when he tweeted that he believed climate change was a manmade hoax created by China in order to impair American competitiveness. His 2016 presidential campaign also saw a great emphasis on reviving the coal industry, which he said was under strain because of environmental regulations.

Ever since, both he and some conservative Republicans, have continued to deny or belittle climate change, an undeniable and science-backed reality.

Naturally, when the U.S. served its formal notice last year to withdraw from the accord and Trump had announced it in a televised speech on June 1, 2017, just one year after the country had signed it, it sent shockwaves across the globe.

Branding it a "very unfair at the highest level to the U.S.," Trump went as far as to claim that in the event the deal was fully implemented, it would have cost the U.S. $3 trillion and 6.5 million jobs. However, Trump was called out for cherry-picking statistics from a report that did not take into account all the potential benefits from avoided emissions.

Statistics show the opposite. A national energy innovation mission adopted by the U.S. for clean innovation investments could create 1 million jobs, a study found. Similarly, a lack of action on climate change policies over the next 50 years was projected to cost Australia $2.4 trillion dollars and over 880,000 jobs, according to a report by Deloitte Access Economics.

Fast forward to 2020, Trump described the Paris climate deal as a "complete disaster from our standpoint" during his first presidential debate with Democratic nominee Joe Biden, while his rival vowed that he would right this mistake and rejoin the agreement if he was elected.

Why is this exit so important?

Two countries in the world, namely China and the U.S., are responsible for 40% of the greenhouse gas emissions that cause global warming, according to studies by the European Commission Joint Research Center and the Netherlands Environmental Assessment Agency in 2017.

With a population of over 328 million, the U.S. holds just 4.25% of the world population; however, it is also the biggest historical contributor to climate change and the second-biggest emitter of carbon emissions.

What are the impacts of the U.S.’ withdrawal?

The U.S.' stepping back from its climate commitments as part of the Paris deal means that 3 billion more tons of carbon dioxide will be released into the atmosphere every year, which will cause a global temperature increase of approximately 0.1 to 0.3 Celsius degrees. And according to the Climate Action Tracker (CAT), the U.S.’ withdrawal means the carbon emissions emitted by the country will be at least 3% higher by 2030, which endangers the 1.5-degree goal set by scientists.

One of the biggest concerns about the U.S.’ move is the snowball effect that it has in regard to international agreements. If one country decided to renege on its commitment and try to renegotiate its way back in with fewer obligations, other countries might also follow suit, damaging efforts to reach global targets in the fight against climate change.

That could have devastating effects on the environment. According to research by CAT, Climate Analytics and the NewClimate Institute, if no country on Earth implements policies to actively combat climate change, global warming is expected to reach a baseline of 4.1-4.8 degrees Celsius above pre-industrial averages by the end of the century. This is more than twice the 2-degree limit deemed the "safe" upper limit by scientists.

With the existing policies of nations around the world, emissions could partially be reduced, and this warming projection could be lowered to about 2.9 Celsius. If the Paris Agreement’s pledges and targets are taken into account, it could limit this figure further down to 2.7 degrees.

Niklas Hohne, a climate scientist at Wageningen University in the Netherlands, and many others believe the results of the election could change global approaches to the problem.

"That election could be a make or break point for international climate policy,’’ said Hohne, speaking to The Associated Press (AP).

The U.S. withdrawal will also have noticeable effects on Earth and its ecosystems as we know it today, experts said.

"Losing most of the world’s coral reefs is something that would be hard to avoid if the U.S. remains out of the Paris process. At the margins, we would see a world of more extreme heatwaves," said climate scientist Zeke Hausfather of the Breakthrough Institute in Oakland, California, as quoted by AP.

Ever since Trump announced his intentions to abandon the Paris Agreement, he has increasingly reversed environmental initiatives launched by his predecessors.

The U.S. Department of Energy even found that except for the slowdown spurred by COVID-19 lockdowns, U.S. carbon emissions dropped by less than 1% a year between 2016 to 2019.

Other nations will also have to do more to limit carbon pollution with the U.S.' exit.

"In terms of leadership, it will make an immense difference," Cornell University climate scientist Natalie Mahowald said.

For every ton of carbon pollution the U.S. promised to cut, the rest of the world said it would match it by 5 tons. In that sense, the U.S. was a crucial part of the agreement, according to climate modeler Trevor Houser from the Rhodium Group and climate scientist Zeke Hausfather.

Houser, in collaboration with research group Climate Action Tracker (CAT), also compared Trump's and Biden's climate goals, creating 10-year scenarios for greenhouse gas emissions. Under Trump's leadership, the U.S. would be emitting 11% more emissions than under Biden's goals, which would equate to about a 6-billion ton difference.

CAT says in the event that Biden manages to reach his goal of zero net carbon emissions by 2050, the Earth will be one-tenth of a degree Celsius cooler.

Of course, even if Biden is elected and he stays true to his promise, the U.S. still won’t have re-entered the pact until his inauguration in January. However, all experts concur that a few months is a small price to pay when considering four years without.

If the U.S. remains out of the climate pact, today’s children are "going to see big changes that you and I don’t see for ice, coral and weather disasters," Stanford University's Rob Jackson told the AP.

Under the Obama administration, the U.S. had also committed to contributing $3 billion to the Green Climate Fund. The fund, created to help poorer countries adapt to climate-related changes and implement policies, had set itself a goal of jointly mobilizing $100 billion a year by 2020.

However, when Trump became president, he moved to withhold $2 billion, and in 2019, the U.S. refused to contribute. That same year, 27 countries' contributions reached $9.8 billion.

The U.S. pullout means reduced financial aid to the fund and a negative impact on climate change research. It also hinders progress in reaching the goals set by the Paris Agreement and renders the U.S free of contributing to future annual assessments and reports by the U.N.'s Intergovernmental Panel on Climate Change (IPCC).

What is global warming and why is it worrying?

Global warming is what it sounds like; it is essentially our planet – its surface, oceans and atmosphere – overheating. It occurs as a result of greenhouse gases accumulating in our atmosphere, which cloaks Earth in a protective and temperature-regulating layer. As greenhouse gases such as carbon dioxide, methane and ozone, which make up the atmosphere, are more complex than other gas molecules, they can absorb or radiate heat. Thanks to this "greenhouse gas effect," our planet is not a cold icy rock hurling through space, and its temperature remains warm enough and stable enough to support human life.

However, as with all things, it is all about balance. Once the concentration of greenhouse gases exceeds what is considered normal, the Earth's temperature sees rapid and unusual increases in temperature owing to these gases' abilities to radiate heat back and trap it in the atmosphere.

The burning of fossil fuels such as oil, coal and natural gas as well as fertilizers used for agriculture and livestock activities all contribute to throwing off this atmospheric balance of gases and temperature regulation. This means our world is turning into a sauna, and we won't be able to crack open a window or door. Drought, famine and floods will be close behind.

What is the Paris Agreement and how does it tie in?

The Paris climate deal, approved by more than 190 countries in 2015, aims to reduce global greenhouse gas emissions by 56 billion tons by the year 2030, phase out the use of fossil fuels, encourage renewable energy and pursue efforts to keep the global temperature increase below 1.5 degrees compared with the pre-industrial era by the end of this century. This figure was recently revised down from 2 degrees after experts highlighted the direness of the situation.

Each country has its own climate targets within the framework of the agreement, which is not legally binding as it is not classified as a treaty. The agreement makes it voluntary for countries to set goals to curb carbon emissions and to increase them over time, with new goals set every five years. The only mandatory part of the agreement is the tracking and reporting of carbon pollution. The U.S.' climate targets foresee the country reducing its greenhouse gas emissions by 26% to 28% by 2025.

a. The 1.5-degree target

Climate scientists have redefined the global temperature rise limit they have deemed "safe" for climate change in the last few years.

For decades, researchers argued that the worst effects of the climate crisis could be avoided if the global temperature rise was kept below 2 degrees Celsius until the end of the 21st century.

The countries that signed the Paris agreement had also made their commitments, according to these predictions, but now experts agree that this temperature increase limit should be 1.5 degrees, not 2.

According to the World Meteorological Organization, from the years when temperature measurements first began, the hottest years measured have been experienced in the last 22 years, with the top four being between 2015 and 2018. For example, in the first 10 months of 2018, the average global temperature was about 0.98 Celcius degrees above the average temperature between 1850 and 1900.

If this trend continues, by the year 2100, the average annual temperature across the world may increase by 3 to 5 degrees Celsius.

One degree may not sound like that much of an increase, but the U.N. Intergovernmental Panel on Climate Change (IPCC) states that if countries do not take action, we will face destructive changes: sea levels will rise, ocean water temperature and acidity will increase and the production of basic food products such as rice, corn and wheat will be under great risk.

b. Why is 2 degrees too much?

If measures are inadequate and the average global temperature increases by 2 degrees, it will have irreversible effects, experts say. The first apparent effect of this warming is the acceleration of the melting of glaciers. Melted ice will soon inundate human settlements at sea level and create a mass exodus of climate refugees. Coupled with scorching heat, which will bring on drought and famine, and a heightened risk of severe storms and freak weather events, experts are reiterating that the world must act swiftly.

Here's what a difference half a degree can make. If the planet warms 2 degrees compared with the Industrial Age instead of 1.5: