Emission cuts: Why sooner is better than later

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We are set to exceed a temperature rise of 3°C this century, despite the growing number of net-zero pledges.[1]Twenty five countries have 2050 net-zero targets either in law, in proposed legislation or in policy documents, while more than 100 nations are considering it. Two nations, Bhutan and Suriname, have … Continue reading Delays to emission cuts mean more emissions and, therefore, more warming – even if we get to net-zero by 2050. Cuts are needed now, in every nation, every year, to avoid ecological disaster. And they need to be transparent so governments can be held to account. 

If the atmosphere was a bucket, adding CO2 is like filling the bucket with water. Net-zero is achieved when what flows in is balanced by what flows out, leaving the water level stable. And the amount of CO2 in the atmosphere determines peak temperature, so the fuller the atmospheric bucket at net zero, the warmer it will be. This is why not all net-zero futures are equal. 

CO2 is cumulative – the more we emit, the warmer it will get

  • We are adding CO2 to the atmosphere at a rate 10 times faster than any other period in the last 66 million years. The global temperature rise of 1.06-1.2°C since the pre-industrial period is a direct result of cumulative CO2 to date. However, due to the long atmospheric lifetime of CO2, stopping emissions does not lead to a rapid reduction in temperature.  
  • The carbon budget is a simple way of measuring how much more CO2 can enter the atmosphere before we overshoot our temperature goals. In 2018, we only had ~ 420 GtCO2 left in the budget to stand a 67% chance of keeping warming below 1.5°C, according to UN climate science body, the IPCC. In the last two years, well over 80 GtCO2 have been emitted – so at current rates we will use up the rest of our budget in less than a decade. Emissions from committed and existing fossil fuel infrastructure alone could emit about 658 GtCO2 within that timescale.
  • Methods of carbon removal range from enhancing natural carbon drawdown through reforestation and the protection of nature to ‘negative emissions technology’, like direct air capture (DAC) and bio-energy with carbon capture and storage (BECCS), which are still in early development. Protecting nature is seen as the best way to manage carbon removal, but there are still concerns about how this could be done. Crucially, the slower our short-term mitigation, the more we will end up needing negative emissions technology, says CICERO.

Overshooting climate targets could lead to serious long-term damage  

  • When climate scientists discuss future scenarios with “overshooting”, they are talking about what will happen to the planet when the global average temperature exceeds a set target – like 1.5°C – and is then lowered through carbon dioxide removal. 
  • Today, over 90% of the emissions pathways consistent with 1.5°C in the long-term include an overshoot by 2050, according to the IPCC. The scenarios were published in 2018, but so far governments have not scaled carbon removal technology – for example, only five BECCS plants are in operation, capturing 1.5 million tonnes of CO2 – only 3% the annual emissions of Sweden. 
  • Scientists are increasingly concerned about overshooting. Growing research shows that, for the same end-of-century temperature increase, an overshoot with carbon removal later is likely to lead to more climate damage than if we get there with no overshoot.[2]Zickfeld, K. and Herrington, T., 2015. and Ricke, Katharine L., and Caldeira, K., 2014 and Tachiiri, K., Hajima, T. and Kawamiya, M., 2019.
  • Overshooting could lead to the loss of species habitats and long-term detrimental impacts on marine ecosystems, and is likely to leave the ocean deoxygenated and acidic

We need transparent climate plans that mitigate all greenhouse gases

  • CO2 is not the only greenhouse gas. Concentrations of methane and nitrous oxide, also released through human activities, are now higher than at any point in the last 800,000 years. In contrast to CO2, mitigating some of these gases can have a more immediate impact on temperature due to their shorter lifetime in the atmosphere. Cutting some non-CO2 emissions is seen as a ‘win-win’ policy option, as their reduction will both reduce warming and improve air quality. 
  • We need transparency. For example, the announcements by California and China to go “carbon-neutral” by 2045 and 2060, respectively, does not mean the same thing – China seems to be aiming for CO2 neutrality, while California is aiming to mitigate all greenhouse gases.

Action on climate benefits nature, health, employment and equity 

  • Globally, nature is declining at rates unprecedented in human history due to the climate and ecological crisis. Current rates of global species extinction are tens to hundreds times higher than the average over the last 10 million years, and accelerating. Conserving and restoring ecosystems increases their resilience to climate change. Nature can be one of our most cost-effective allies, protecting poor communities and supporting sustainable development.
  • Health professionals have warned that a stable climate is the number one determinant of human health. Limiting temperature rise to 1.5°C could prevent ~150 million premature deaths over the 21st century. Transitioning away from fossil fuels and adopting clean energy could be one of the greatest public health opportunities this century. The more stringent these mitigation measures, the larger the public health benefits – from improvements in air quality to reductions in school absenteeism, hospitalisations, premature births, cardiovascular illness and deaths. Globally, the health cost savings from decarbonisation alone could cover the entire costs of its implementation.
  • Low-carbon sectors have significantly higher job creation potential than fossil-fuel sectors. Each dollar invested in energy efficiency or the renewables sectors creates more than twice as many jobs compared to the fossil fuel sectors. The transition of employment from fossil-fuel to low-carbon industries will also result in the improved occupational health of employees.
  • Recent estimates show that climate solutions could cost around USD 25 trillion globally, but that the resulting savings are five to six times larger. Keeping global temperatures below the 1.5°C target could yield global net economic savings of USD 145 trillion, not including the many trillions of dollars saved by improving public health and avoiding climate damages.

Acting now is key to climate justice

  • With current emissions trends, our chance of staying below 2°C is only 5%. To change this, we must act now. To have a chance at 1.5°C, UNEP states we need to bring annual global GHG emissions down to 25 Gt CO2e by 2030. For this we need net-zero targets with ambitious near-term action, accompanied by disclosure measures on how to achieve and monitor these goals.
  • Today, marginalised communities are disproportionately affected by climate change, even though they contribute the least to it. G20 nations – responsible for over 78% of emissions – fall short on proving that their climate policies will achieve the goals they have committed to.[3]G20 Zero-Carbon Policy Scoreboard, Bloomberg New Energy FInance, 2021 Fifteen of the 20 members have not even committed to a timeline for achieving net-zero emissions, and the world is set to fail key biodiversity targets and 80% of the SDGs, due to our mismanagement of nature. 
  • Increasingly, people are holding governments and leaders to account for the climate crisis. Nearly a third of all historical climate litigation cases were filed in the last five years, according to the Climate Change Laws of the World Database (120 out of 391 cases from 27 countries). Of these 120 cases, 76% of the legal challenges were against governments and 21% were against corporate or private entities.
  • Governments are pouring trillions of dollars into COVID-19 recovery but only 12% so far contributes to a green recovery, despite the fact that 25% of predicted emissions by 2030 could be cut, according to UNEP. It is crucial to demand that COVID-19 response goes towards a just, green recovery that mitigates climate change and protects those it impacts most. 


1 Twenty five countries have 2050 net-zero targets either in law, in proposed legislation or in policy documents, while more than 100 nations are considering it. Two nations, Bhutan and Suriname, have already reached net-zero.
2 Zickfeld, K. and Herrington, T., 2015. and Ricke, Katharine L., and Caldeira, K., 2014 and Tachiiri, K., Hajima, T. and Kawamiya, M., 2019.
3 G20 Zero-Carbon Policy Scoreboard, Bloomberg New Energy FInance, 2021
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