But any impact on carbon dioxide (CO2) concentrations – the result of cumulative past and current emissions – is in fact no bigger than the normal year-to-year fluctuations in the carbon cycle and the high natural variability in carbon sinks like vegetation.

Despite 2020's reverse trend, 2021 emissions are expected to again grow by nearly 5 per cent, to 33 billion tonnes.

CO2 concentrations are currently near 420 parts per million (ppm for short), setting a record high amount despite the ongoing pandemic.

The last time the Earth experienced a comparable concentration of CO2 was 3 million to 5 million years ago, when the temperature was 2 to 3 degrees Celsius warmer and sea level was 15 to 25 metres higher than now.

WHY ARE EMISSIONS STILL GROWING?

Climate change is driven by the combustion of fossil fuels, which contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years. Fossil fuels are consumed at a rate of 171,000kg of coal, 11.6 million litres of gas, and 186,000 litres of oil per second.

In 2019, global carbon emissions from fossil fuels and industry reached a high of 36 billion tonnes.

The carbon-based fossil fuels are used for transportation, electrical generation, cement manufacturing and more. The climate crisis caused by carbon-based fuels is amplified by deforestation, agriculture, and many other practices.

Each year we pump more CO2 into the atmosphere than natural processes can remove, causing global emission levels to rise. Over the past 60 years, the annual rate of increase in atmospheric CO2 is roughly 100 times faster than the increases that occurred during the last ice age.

The total warming effect from human-generated greenhouse has increased by 45 per cent over 1990 to 2019.

Progress in mitigating this threat is intermittent at best, with CO2 emissions continuing to rise.

CHANGES TO ECONOMY, NOT BEHAVIOUR, NEED TO BE MADE

Given the astronomical amount of CO2 we emit yearly, structural changes to the economy are needed, and not just behavioural changes such as flying or driving less.

Most of the fall and subsequent rebound of CO2 emissions has come from road transport. Deserted streets and empty highways swiftly became the norm during lockdowns, as people were ordered to stay at home except for emergencies.

The actions that do make a difference include investment in renewable energy, low-carbon infrastructure, and plans to make buildings more energy efficient.

Renewable energy is becoming more and more affordable. The costs of solar and wind have fallen dramatically in recent years and will continue to do so.

But even though we know what to do, the carbon intensity of the energy system has remained unchanged since 1990. Global fossil fuel consumption subsidies increased by 50 per cent from 2016 to 2018.

While coal-fired generation fell in 2020, the increases of the previous few years offsets this, rendering the level of coal generation no different from that of 2015.

CAN WE HALT THE CLIMATE CRISIS?

The science of climate change describes a range of possible futures, which are largely dependent on the degree of action or inaction in the face of a warming world.

The policies implemented at COP26 will have far-reaching effects.

At COP26, governments had to make progress in closing three major gaps: A gap in targets to reduce emissions, a gap in rules to deliver and monitor progress, and a gap in financing climate solutions.

We expected leaders to agree to a step change in the pace and scale of climate action.

But based on nations that submitted targets, the world is now on track to warm 2.4 degrees Celsius since pre-industrial times by the end of this century.

That is a far cry from the 2015 Paris climate deal overarching limit of 1.5 degrees Celsius or even its fallback limit of 2 degrees Celsius.

This was recognised in the final agreed COP26 document by including a pledge that revised (and more ambitious) plans for cutting emissions are to be submitted by each nation in a year’s time.

The COVID-19 pandemic is not a solution for climate change.

But the needed changes are economically affordable, technically possible and would affect our everyday life only marginally.

The world’s largest economies are spending trillions of dollars to help their economies recover from the COVID-19 pandemic but aren’t investing enough in a green recovery.

According to the latest UN Environment Programme Emissions Gap Report, of the US$16.7 trillion that has been spent globally to May 2021 on COVID-19 recovery packages, only US$438 billion is likely to reduce greenhouse gas emissions.

Halting the climate crisis is still possible if we scale up the global response. But the window is closing fast.

Armed with education about how the Earth works, if we act boldly and swiftly, if we set aside our political interests in favour of the air that our young people will breathe, and the food they will eat, and the water they will drink; if we think about them and their hopes and dreams, then we will act, and it won’t be too late.

Professor Benjamin Horton is Director of the Earth Observatory of Singapore and a professor at the Asian School of the Environment in Nanyang Technological University.