Briefing Note 1 – Where Are We in Achieving Net Zero?


How Can We Reduce Emissions Through Energy Efficiency?


Up to the present day, improvements in efficiency of the fossil energy production system have saved 30 times the quantity of emitted CO2 than have been saved through the production of renewable energy. In absolute terms, these efficiency improvements have saved the equivalent of 25 years of present-day CO2 emissions. However, renewables still remain considerably more visible in the mass media and scientific literature. 


Energy efficiency has far larger potential to reduce emissions than can be achieved through the use of renewables. While efficiency improvements such as commercial building retrofits incur large upfront costs, they typically pay back their costs within a few years due to large energy savings.


There are multiple examples of efficiency improvements such as the design of pipes and ducts for oil transportation, the use of carbon fibre in vehicles resulting in a decrease in weight and a corresponding increase in fuel efficiency, and improvements in logistics resulting in fewer empty truck movements. These efficiency improvements means that oil company owners are far more at risk from competition and corresponding low prices, than anything else.


A rapid transition to a low carbon energy system is well underway and emissions reductions due to efficiency savings are still accelerating. This may provide good reason for optimism over the ambitious temperature and emissions targets of the Paris Agreement. However, the current Nationally Determined Contributions (NDCs) are are likely to result in 3°C of warming by the end of the 21st century.


What Will Be Required for the UK to Achieve Net Zero Emissions by 2050?


There are two levers associated with stabilising global temperatures (whether at 1.5°C or 2°C): the date when net zero emissions of CO2 are achieved and the pathway of non- CO2 forcing.  


A key feature of the warming associated with CO2 emissions is that peak induced warming is proportional to the cumulative amount of CO2 emitted.


When it comes to Short-Lived Climate Polluters (SLCPs) such as methane, it is not the cumulative amount of emissions that determines the ultimate level of warming, but when the annual emissions of the SLCPs stabilise. 


With current emission levels, there is warming of 0.2-0.25°C per decade. Given that there has already been 1.1°C of warming, we have about 15-20 years until we reach 1.5°C if we continue to increase at current emission levels.


We would need to follow a straight line mitigation pathway to net zero emissions over the course of 30-40 years to cap the rise in temperatures at 1.5°C. For every decade of delay in starting this steep pathway to net zero, it means a commitment to an additional 0.2-0.25°C of warming.


What Is the Role of the Public in Achieving Net Zero?


The majority of voters in the UK now list climate change as one of their key concerns and those who organise demonstrations about the climate crisis claim that they have had a key role in the facilitation. 


Achieving net zero by 2050 is too late, certainly for the biodiversity in coral reefs and rainforests. It is possible to achieve net zero by 2025, however this would require significant political will and societal changes.


Climate activists are encouraged to show solidarity with climate scientists. However, there are tensions between climate activist claims and the predictions of climate scientists, who are accused of being too conservative.


The relationship between climate activists and climate scientists needs to improve, which poses the question of how they can better work together to achieve a common goal. Scientists ask activists to get behind the science, rather than attacking it, while activists claim that they are doing a better job of communicating the risks of climate change to the public, and are providing the political pressure to take the climate action that the scientists are recommending.


What Does Achieving Net Zero Conclude and Recommend?

  • Energy efficiency is a highly underrated method of reducing emissions;


  • There is evidence that a major transformation towards a low carbon energy system is underway


  • Every decade delay in beginning full mitigation leads to an additional 0.2-0.25°C of warming;


  • There is tension in the relationship between climate activists and climate scientists which can be counterproductive