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In recent years, numerous countries around the world have announced their intention to reduce carbon emissions by a significant margin in the upcoming decade. Moreover, many of these countries have made major commitments to reach “net-zero emissions” by 2050.

This can be demonstrated by the fact that more than 190 countries (plus the European Union) have joined the 2015 Paris Agreement, a legally binding international treaty that aims to mitigate the impact of climate change.

To meet the target set by the Paris Agreement – limiting global temperature rise to 1.5 degrees Celsius above pre-industrial levels – global greenhouse gas emissions need to reach net zero by 2050.

Therefore, the term’ net zero’ has almost become a worldwide rallying cry, frequently cited by government agencies, nonprofits, and corporations as a necessary step toward minimizing the negative impact of climate change.

The latest research seems to support this claim, with the scientific community warning that greenhouse gas emissions need to drop by half in the next decade to avoid a climate-related catastrophe.

Net zero is the state where the amount of greenhouse gas being released into the atmosphere is the same as the amount of greenhouse gas being removed from the atmosphere during the same period.

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The world’s largest emitters of carbon dioxide, the United States and China, have also communicated their versions of such net-zero targets. China has pledged complete carbon neutrality by 2060, while the US has recently announced a new target to reduce greenhouse gas emissions by 50-52 percent by 2030 (taking 2005 as the base year for the calculations). 

How is Net-Zero Calculated?

While these developments are promising, all the pledges and commitments from governments, businesses, and civil society would mean nothing if we don’t understand how exactly ‘net zero’ is calculated. Setting goals is of little use unless we can measure our progress (or lack thereof).

So, let’s dive straight in and try to understand the math behind net zero, the environmental buzzword of our times.

In simple terms, net zero refers to:

a state wherein the amount of greenhouse gases released into the atmosphere is equal to the amount that is removed from the atmosphere, during the same time period. This can occur only when there is perfect balance between the sources and sinks of the greenhouse gases released through human activity.

The Formula For Net Zero:

Greenhouse Gas Emissions – Greenhouse Gas Removed From the Atmosphere = 0

To achieve net zero, governments and corporations must first focus on reducing anthropogenic emissions as much as possible. Vehicles and factories powered by fossil fuels should be slowly phased out, so renewable energy sources can later replace them.

However, some sources of greenhouse gas emissions, such as aviation and agriculture, cannot be easily replaced or eradicated. For such cases, governments and communities must invest heavily in carbon removal methods and technologies.

Removing greenhouse gases from the atmosphere can compensate for some of the unavoidable anthropogenic emissions under our current circumstances. Carbon removal can be achieved through extensive afforestation, reforestation, and direct air capture and storage (DACS) technology.

Calculating the Timeframe and Logistics of Net-Zero

Courtesy of Statista

Countries that joined the Paris Agreement have pledged to limit global warming to less than 2°C above pre-industrial levels. Ideally, global temperatures should not increase more than 1.5°C above that which existed before the Industrial Revolution.

Currently, global temperatures are approximately 1.1°C higher than they were two hundred years ago. This rise in temperature has already led to natural calamities like intense storms, devastating heat waves, and the melting of polar ice.

Therefore, to reach the temperature goals set out during the Paris Agreement, we must aim to reduce emissions by the below timelines:

  • Carbon neutrality (net-zero carbon dioxide emissions) must be achieved between 2044 and 2052, if global warming is limited to 1.5°C above pre-industrial levels.
  • The total emission of all greenhouse gases – including methane, nitrous oxide, and chlorofluorocarbons – must reach net-zero levels by the year 2068.
  • If we can achieve net-zero emissions before hitting these deadlines, the rise in global temperatures will not exceed 1.5°C, even temporarily.
  • If we only achieve net zero very close to the given deadlines, then the rise in global temperature might surpass 1.5°C for a short while before dropping back down once again.
  • To limit global warming to 2°C above pre-industrial levels, on the other hand, we will need to reach carbon neutrality between 2070 and 2085. The emission of all other greenhouse gases (apart from CO2) will have to reach net-zero levels by 2100, at the latest.

The time frame for reaching carbon neutrality (or net-zero carbon dioxide emissions) is tighter than that for other greenhouse gases like nitrous oxide and methane. This is because carbon dioxide comprises most of all greenhouse gas emissions, accounting for almost 75 percent of the total, worldwide emissions.

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Moreover, some greenhouse gases are harder to phase out than others. For instance, the methane produced by farm animals such as goats, cows, and sheep might be a necessary evil, at least for the time being. This is because these animals are needed to produce meat and dairy. And while we can all aim to reduce the proportion of animal-based products in our diets, it is unlikely that humans will shift to a completely plant-based diet soon.

Methane is also produced during rice agriculture, albeit to a lesser degree than cattle rearing.

The problem is that methane and other potent greenhouse gases can effectively trap the sun’s heat and drive temperatures higher, particularly in the short term. They must, therefore, be removed from the atmosphere – through reactions with the hydroxyl (OH) radicals present in the troposphere, DACS technologies, and other removal methods.

Much more has been said about the concept, and in this other article here, we debunk and address many misconceptions.

The Role of Individuals and Communities

Government action is necessary, but individuals, families, and communities can also help push us closer to the net zero emissions goal by being mindful of their day-to-day choices and activities.

For instance, you can build a net-zero home to minimize your household carbon footprint with the latest energy-efficient design, insulation, and appliances for less than you might think! This might inspire other community members to join the sustainable housing trend and invest in net-zero properties.

Similarly, you can help reduce methane production by shifting to a more plant-based diet and reducing the proportion of meat and dairy in your everyday meals. You can also invest in solar panels and other renewable energy sources, take public transportation whenever possible, and insulate your home properly to reduce the energy required for temperature regulation.

Over time, these seemingly small and inconsequential choices will inspire others and significantly impact our net-zero goals and calculations.

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