COURTESY  :  www.wri.org

Net zero

The latest climate science is clear: Limiting global warming to 1.5 degrees C (2.7 degrees F) is still possible. But to avoid the worst climate impacts, global greenhouse gas (GHG) emissions will need to drop by half by 2030 and reach net-zero around mid-century.

Recognizing this urgency, a rapidly growing number of national government, local government and business leaders are making commitments to reach net-zero emissions within their jurisdictions or businesses. To date, over 80 countries have communicated such “net-zero targets,” including the world’s largest emitters (China, the United States, the European Union and India). On top of that, hundreds more regions, cities and businesses have set targets of their own.

But what does a net-zero target mean, what’s the science behind net-zero and which countries have already made such commitments? Here are eight common questions and answers about net zero:

1. What Does It Mean to Reach Net-Zero Emissions?

Net-zero emissions will be achieved when all GHG emissions released by human activities are counterbalanced by removing GHGs from the atmosphere in a process known as carbon removal.

First and foremost, human-caused emissions (such as those from fossil-fueled vehicles and factories) should be reduced as close to zero as possible. Any remaining GHGs should then be balanced with an equivalent amount of carbon removal, which can happen through things like restoring forests or using direct air capture and storage (DACS) technology.

2. When Does the World Need to Reach Net-Zero Emissions?

Under the Paris Agreement, countries agreed to limit warming well below 2 degrees C (3.6 degrees F), ideally to 1.5 degrees C (2.7 degrees F). Global climate impacts that are already unfolding under the current 1.1 degrees C (1.98 degrees F) of warming — from melting ice to devastating heat waves and more intense storms — show the urgency of minimizing temperature increase.

The latest science suggests that reaching the Paris Agreement’s temperature goals will require reaching net-zero emissions on the following timelines:

• In scenarios limiting warming to 1.5 degrees C, carbon dioxide (CO2) needs to reach net-zero between 2044 and 2052, and total GHG emissions must reach net-zero between 2063 and 2068. Reaching net zero earlier in the range avoids a risk of temporarily overshooting 1.5 degrees C. Reaching the top of the range almost guarantees surpassing 1.5 degrees C for some time before it eventually drops down.
• In scenarios limiting warming to 2 degrees C, CO2 needs to reach net zero by 2070 (for a 66% likelihood of limiting warming to 2 degrees C) to 2085 (with a 50-66% likelihood). Total GHG emissions must reach net-zero by the end of the century or beyond.

The Special Report on Global Warming of 1.5˚C, from the Intergovernmental Panel on Climate Change (IPCC), finds that if the world reaches net-zero emissions by 2040, the chance of limiting warming to 1.5 degrees C is considerably higher. The sooner emissions peak, and the lower they are at that point, the more realistic achieving net zero becomes. This would also create less reliance on carbon removal in the second half of the century.

This does not suggest that all countries need to reach net-zero emissions at the same time. The chances of limiting warming to 1.5 degrees C, however, depend significantly on how soon the highest emitters reach net-zero emissions. Equity-related considerations — including responsibility for past emissions, equality in per-capita emissions and capacity to act — also suggest earlier dates for wealthier, higher-emitting countries.

Importantly, the time frame for reaching net-zero emissions is different for CO2 alone versus for CO2 plus other GHGs like methane, nitrous oxide and fluorinated gases. For non-CO2 emissions, the net zero date is later because models suggest that some of these emissions — such as methane from agricultural sources — are more difficult to phase out. However, these potent but short-lived gases will drive temperatures higher in the near-term, potentially pushing temperature change past the 1.5 degrees C threshold much earlier.

Because of this, it’s important for countries to specify whether their net-zero targets cover CO2 only or all GHGs. A comprehensive net-zero emissions target would include all GHGs, ensuring that non-CO2 gases are also reduced.

3. What Needs to Happen to Achieve Net-Zero Emissions?

Policy, technology and behavior need to shift across the board. For example, in pathways to 1.5 degrees C, renewables are projected to supply 70-85% of electricity by 2050. Energy efficiency and fuel-switching measures are critical for reducing emissions from transportation. Improving the efficiency of food production, changing dietary choices, halting deforestation, restoring degraded lands and reducing food loss and waste also have significant potential to reduce emissions.

It is critical that the structural and economic transition necessary to limit warming to 1.5 degrees C is approached in a just manner, especially for workers tied to high-carbon industries. The good news is that most of the necessary technologies are available and increasingly cost-competitive with high-carbon alternatives. Solar and wind now provide the cheapest power available for 67% of the world. Markets are waking up to these opportunities and to the risks of a high-carbon economy, and shifting accordingly.

Investments in carbon removal techniques are also necessary. The different pathways assessed by the IPCC to achieve 1.5 degrees C all rely on carbon removal to some extent. Removing CO2 from the atmosphere will compensate for emissions from sectors in which reaching net-zero emissions is more difficult, such as aviation. Carbon removal can be achieved by several means, including through land-based approaches and technological approaches.

4. Is the World on Track to Reach Net-Zero Emissions on Time to Avoid the Worst Climate Impacts?

No — despite the enormous benefits of climate action, progress is happening far too slowly for the world to hold temperature rise to 1.5 degrees C (2.7 degrees F).

Significant gains have been made to reduce emissions, such as increasing the share of renewables in electricity generation. However, efforts to phase out unabated coal remain well off-track and must decline five times faster by 2030. Similarly, the share of electric vehicles in light-duty vehicle (LDV) sales hit 4.3% in 2020, increasing at a compound average growth rate of 50% over the last five years. Although promising, such progress still needs to accelerate significantly to help reduce the transport sector’s emissions and reach 75-95% of LDV sales by the end of this decade, a target aligned with limited warming to 1.5 degrees C.

Additionally, action must be taken to reverse course in cases, where change is at a standstill or headed in the wrong direction entirely. For instance, the world needs to drastically slow deforestation and increase tree cover gain three times faster by 2030.

5. How Many Countries Have Net-Zero Targets?

Global momentum for setting net-zero targets is growing quickly, with key economies like China, the United States and the European Union articulating such commitments. Bhutan was the first country to set a net-zero target in 2015. Now over 80 countries, representing more than 70% of global emissions, are covered by a net-zero target.