Where do our emissions come from?
Part 2 of our Energy & Emissions series of blogs.
In this blog, we will explain the different types of greenhouse gas and fossil fuel, as well as try and find the source of the world’s emissions. Which sectors emit the most? Which fuels produce our electricity and energy? And how has the UK managed to reduce its CO2 emissions?
Greenhouse Gases & Fossil Fuels
A greenhouse gas (GHG) is a gas that contributes to climate change via the greenhouse effect, explained in our blog here.
The most significant GHG is Carbon Dioxide (CO2) but Methane (CH4), water vapour (H2O), nitrous oxide (N2O), and ozone (O3) all contribute to the greenhouse effect to varying degrees.
CO2 is produced by the burning of fuels such as coal, natural gas and oil. These fuels are collectively known as fossil fuels because they were formed from the remains of living organisms via incredibly slow geological processes over millions of years.
It is important to note that not all fossil fuels produce the same amount of CO2 for the same amount of energy output, some are worse polluters than others. Even forms of renewable generation emit some CO2 during the construction or the transportation of components, however coal, oil & natural gas are by far the worst emitters of CO2.
This might indicate that coal is predominately to blame for global emissions, and while it has certainly had a large role, oil and gas have also made significant contributions, especially in the last 50 years. Industrial processes such as the production of cement and flaring have also contributed to the rise in emissions and will need to be curtailed if the world is to reach Net-Zero.
Getting to the source of our emissions
The majority of GHG emissions come from the burning of fossil fuels to produce energy to heat our homes, power our vehicles or produce our electricity. Other sources of emissions come from land use, agricultural livestock, cement production, methane flaring and other industrial processes.
Where do we get our energy from?
It is clear that energy is the largest source of global emissions. So how are we producing energy at the moment? Well, despite increases in the amount of renewable energy being produced the world is still incredibly reliant on fossil fuels for electricity generation, transportation and heating.
This reliance on fossil fuels is not changing nearly quickly enough. In fact, the only fossil fuel that is seeing its use decline is coal. On a positive note, the world is at least moving towards clean energy, with 1113 TWh more clean energy being used in 2019 than 2018, the problem is that at the same time consumption of gas and oil continued to rise.
Which sectors emit the most?
Globally, producing Electricity & Heat remains the largest source of CO2 emissions. With Transport the second largest and Manufacturing & Construction coming in third. This is why so much focus on climate action concerns electricity generation, the phase-out of coal power and increasing the share of renewable generation. It is also why there is a lot of focus on moving away from powering cars with petrol and diesel and moving towards electric vehicles.
The UK as a Case Study
In the UK, emissions from Electricity & Heat have sharply reduced in the last 15 years due to a rapid move away from coal power to natural gas and renewable generation. Coal produced 40% of the UK’s electricity as recently as 2012, in 2019 that proportion was down to just 2% (find more stats about the death of coal in the UK here). Much of that capacity has been replaced by wind power and has also coincided with a reduction in the total amount of electricity required due to advances in energy efficiency. This combination has dramatically reduced the overall emissions of the electricity sector and the country as a whole
However, emissions from many other sectors, including Transport, have stubbornly stayed flat, the need to address Transport emissions led the Government to declare that they will introduce a ban on the sale of new petrol and diesel cars from 2030 onwards.
Despite welcome progress so far, the UK has the ambition to reduce its emissions 78% by 2035 (from 1990) levels and to reach Net-Zero by 2050, so further cuts in emissions need to be made across all sectors of the economy. While certainly important, it could be argued the replacement of coal was the “low hanging fruit” of the UK’s decarbonisation journey, and much more difficult transitions will be required, and fast, if we are to reach Net-Zero.
As for the rest of the world, the first step is to slow and stop the growth of fossil fuel generation. The building of coal plants and the use of coal as a means of producing energy should be the first step nations take to reduce their emissions. Increasing the amount of energy generated from renewables such as solar and wind is crucial, but this generation has to replace fossil fuels, not just be added to them. At the same time, they will have to face the same difficult choices as the UK in terms of how they cut emissions from transport, heating and industrial processes. And the whole world will have to work out how to reduce emissions from the sectors that fall out of each nations emissions arithmetic, namely aviation & shipping.
Our next blog will look at some of these “pathways to Net-Zero” for the UK and for the world as a whole. What will a Net_Zero world look like? How will we get our energy? And how can we get there?