While COVID-19 resulted in reduced CO2 emission levels by putting a stop to many activities and pushing populations into lockdowns worldwide, in 2021 greenhouse gas emission levels bounced back as economies returned to normal life. This means that countries and businesses need to transform the ways they behave to be able to reach net zero by 2050. But what does it mean to reach net zero and will countries succeed in achieving this target?
Even if humanity does stop polluting the planet by reducing the emission of heat-trapping gases to almost zero, the temperature will still increase for a few decades as the ocean has stored heat in its great depths and currents will bring this to the surface for some time. The Earth’s temperature will then begin to stabilize after the stored heat has radiated out. If there was no human involvement at all, nature would gradually eliminate the excess levels of CO2 from the atmosphere, and the Earth’s temperature would slowly begin to fall.
However, what if humans continue to pollute the planet without taking any dramatic action towards the elimination of CO2? In that case, the temperature would be unlikely drop below pre-industrial temperatures of 1.5° Celsius, meaning that global warming will increase the risk of serious negative impacts. The higher the temperature rises beyond the 1.5° Celsius threshold, the greater the risks. Currently, the planet’s temperature exceeds the level of the late 1800s by about 1.1° Celsius. To hold global warming below 1.5° Celsius, humans must decrease emissions by 45% by 2030 and reach zero by 2050.
But what does it mean to reach net zero? Net zero simply means decreasing CO2 emissions to as close to zero as possible. Nevertheless, this will involve enormous effort as achieving net zero will require a complete transformation of production, consumption, and transportation approaches. The energy sector alone accounts for three-quarters of greenhouse gas emissions at present. However, it also plays an essential role in averting the effects of global warming by moving away from traditional energy sources and replacing these with renewable alternatives which is crucial to reaching net zero.
Reducing CO2 emissions to almost zero requires the highest level of commitment from every country. One hundred of the least polluting countries account for only 3% of greenhouse gas emissions, while the top 10 largest CO2 polluters contribute over two-thirds of emissions globally.
Fig.1.Top greenhouse gas emitters
Source: United Nations
In 2021, China, the United States, the EU27, India, Russia, and Japan accounted for 67.8% of global greenhouse gas emissions. These countries account for 62.4% of global GDP and 66.4% of global fossil fuel consumption. Compared to 2020, each of the six largest emitters increased their CO2 emissions in 2021, with India and Russia recording the most significant increase of the six countries, raising their emissions by 10.5% and 8.1%, respectively.
While a growing number of countries, businesses, and other institutions have pledged to reach net zero, the world is not currently on track. According to a report by the International Energy Agency, the Joint Research Centre, and the Netherlands Environmental Assessment Agency, while the pandemic decreased global greenhouse gas emissions by around 5% in 2020, CO2 emissions bounced back by 5.3% in 2021 compared to the previous year.
According to the Net Zero Economy Index which aims to measure the progress that G20 members have made in decreasing energy-related greenhouse gas emissions and decarbonizing their economies, in 2021 the global rate of decarbonization at 0.5% was the lowest in 10 years. To limit global warming to 1.5° Celsius, countries need to maintain a yearly decarbonization rate of 15.2%. Dan Dowling, who leads Net Zero Strategy & Transformation at PwC UK, says:
“Achieving a 15.2% annual rate of decarbonization is now needed to bridge the gap between the climate emergency and a strong and sustainable economy. We’ve seen a willing appetite for change, but this is set against a fragile geopolitical and economic backdrop. Soaring energy prices, and the need to stimulate economic growth following the pandemic, have hampered recent progress. Persevering with action and investment now will set nations on the right path towards a net zero economy.”
Fig.2. Net Zero economy index 2022