2020 could be on track to be another record-setting warm year despite global lockdowns​​​​​​​

People around the world participated in the Global Day of Climate Action on Friday, a reminder that even though we're in the midst of one of the biggest health issues to face humanity, climate change stands to pose an even bigger threat — with increased chances of drought, wildfires, hurricanes, flooding and heat waves.

At the start of the COVID-19 pandemic earlier this year, businesses shuttered and people went into lockdown. As a result, greenhouse gas emissions dropped, including both nitrogen dioxide and carbon dioxide (CO2), two drivers of global warming.

There was some hope that this could be the silver lining to a tragic situation, but the fact is, it's unlikely to make a dent in the upward trend of Earth's rising temperatures.

In fact, the U.S. National Atmospheric and Oceanic Administration's National Centers for Environmental Information (NCEI) recorded that globally, August's land and sea temperatures were the second-highest on record. For North America, it was the hottest August on record, at 1.52 C above average. August also marked the 428th-consecutive month with temperatures above the 20th-century average.

The issue is that CO2 has already accumulated in our atmosphere, and Earth is playing a game of catch-up.

"Carbon dioxide can last thousands and thousands of years in the atmosphere," said Ahira Sanchez-Lugo, a physical scientist who compiles global temperature data at NCEI. "So just because with the pandemic we've seen a reduction in emissions, that doesn't mean that we will see a reduction in global temperatures any time soon."

Climatologist Michael Mann, a professor of atmospheric science at Penn State University, said there's likely to be a drop in emissions but that it won't make a large difference. 

"It will probably lead to a roughly four to five per cent reduction in carbon emissions for 2020. That means a very slightly lower rate of warming," he said. 

Too many blankets

Sanchez-Lugo likes to use the analogy of CO2 acting as Earth's blanket: It's needed in order to regulate the planet's temperature, but additional accumulation is like throwing more and more blankets on top. 

"So that's what's happening right now in that sense: Right now, Earth already has several layers of blankets, and just because we stopped or we've reduced carbon greenhouse emissions recently, that doesn't mean that we're peeling off those blankets," she said. 

Year-to-date, the temperature is 1.03 C higher than the average and is only behind 2016's record warmth of 1.08 C above average. 

The hottest year on record was 2016, reaching 0.94 C above the average. It also marked the third-consecutive year a record was set. But that was also the year of a moderate to strong El Nino, a natural phenomenon that is characterized by warming in the Pacific Ocean — which in turn causes higher temperatures in some regions and greater precipitation in others. 

This year, however, has not been a year of El Nino.

So does this mean we might break the 2016 record without its warming effect?

"Right now, there is about a 55 per cent chance of [2020] being the second warmest," Sanchez-Lugo said, "and ... about a 39 per cent chance of it being the warmest year on record."

While 2020 may not be on top of the list, it's likely that more and more records will be set in the coming years.

A study published in May in the Bulletin of the American Meteorological Society, of which Sanchez-Lugo was a co-author suggested that "there's a greater than a 99 per cent chance that most of the next 10 years through 2028 will be ranked among the top 10 warmest."

The pandemic might be a way of illustrating that countries can reduce their emissions by altering their lifestyles, such as by not commuting to work five days a week, which would be one way to continue to see emissions decrease.

But Mann said big changes need to be made in order to see significant improvement in the decades to come.

"If we can reduce carbon emissions a bit more — about seven per cent a year — for each of the next 10 years, we can stay on a path that stabilizes global warming below 1.5 C, preventing the most damaging and dangerous impacts of climate change," he said.

"However, simple behavioural changes won't get us there. We need systematic change, i.e. policies to rapidly decarbonize our economy."