What is net zero?
Net zero is the balance between the amount of greenhouse gas emissions produced and the amount of these gases that are removed from the atmosphere. We reach net zero when the amount of gases added equal no more than the amount that are taken away.
In order to effectively reach net zero, we have to focus on both routes towards the goal: reducing the production of greenhouse emissions and working to capture and remove existing damaging gases in the atmosphere.
What are greenhouse gases?
The main gases produced in the UK are carbon dioxide, methane, and nitrous oxide. Carbon dioxide is the biggest culprit when it comes to climate change. That’s why terms such as ‘carbon neutral’ and ‘carbon capture’ are commonplace in discussions around combatting climate change worldwide.
Greenhouse gases are most commonly produced by burning fossil fuels. This takes place in power stations (that fuel businesses and homes), during industry production, and through the use of petrol- and diesel-powered vehicles. These contributors are responsible for the majority of carbon released into the atmosphere from the UK.
Waste management (specifically landfill sites) and agriculture are also contributors in greenhouse gas production, primarily through methane and nitrous oxide. The National Farmers’ Union (NFU) has explained that reducing methane and nitrous oxide emissions is more challenging than cutting CO2 because the emissions ‘result from complex and imperfectly understood natural soil and animal microbial processes, a changing climate and the limitations of measurement’.
The UK government’s approach to net zero
The UK’s Climate Change Act of 2008 was the world’s first long-term framework produced by a country to tackle climate change. Prior to this, despite efforts across the globe to fight climate change, a national framework was yet to be established. The act set a legally binding target to achieve an 80% reduction in greenhouse gas emissions by 2050 (the baseline being the emission output in 1990).
With only some improvements over the years, this act had many false starts and it was not until the 2015 United Nations’ Paris Agreement (which saw a global commitment to keeping greenhouse gas emissions below 2° Celsius) that the UK really acted on the importance of tackling climate change. The agreement also acknowledged ‘the fundamental priority of safeguarding food security and ending hunger, and the particular vulnerabilities of food production systems to the adverse impacts of climate change’.
More recently, in 2019, Britain made world history again, becoming the first economy to write net zero emissions into their legislation. The aim of the 2019 net zero policy was to end the UK’s economic involvement in negative climate change over the next 30 years.
Today, when it comes to climate change, the UK government’s main focus is reducing emissions. This is the most accessible way that the UK can control their impact; investing in green and innovative ways to reduce the use of fossil fuels and motivating corporations to take these changes on board.
The majority of greenhouse gas capture occurs naturally in oceans and forests (otherwise known as carbon sinks), so it is important to also acknowledge the integrity of these ecosystems in reaching net zero.
Why should we achieve net zero?
The disastrous negative impact greenhouse gases have on the world is the main reason that reducing them is so important.
Greenhouse gases are capable of absorbing dangerous radiation. This absorption results in the gases trapping and holding heat in the atmosphere surrounding the earth. This heat then creates a greenhouse effect, warming up the earth’s surface.
In order for the global ecosystem to function effectively, it is crucial that we ensure the earth’s surface is at the right temperature. As the climate warms, ice caps melt, destroying ecosystems and causing sea levels to rise. An increased climate temperature also causes animals and plants to become extinct, which in turn reduces food availability to other animals in the food chain causing them to similarly reduce in number. As these ecosystems no longer flourish, the land becomes desolate and unusable.
Humans are also directly impacted by the release of greenhouse gases. Alongside the erosion of the global ecosystem, greenhouse gases have also drastically increased health problems, specifically cardiovascular and respiratory diseases, particularly within cities where pollution is rife. In developing nations, the impacts of climate change can also result in malnutrition, partly due to extreme weather events. These events, often in the form of extreme heat or severe flooding, can result in whole areas, communities, and ecosystems being wiped out.
How does AD contribute to achieving net zero?
Anaerobic digestion (AD) is an essential element in the journey towards net zero. For one, AD breaks down organic matter, most commonly food and animal waste, into CO2, methane, bacteria and water. This breakdown occurs in oxygen-free tanks called digestors, which contain microbes that interact with the feedstock to create gas.
The gas produced in the process is biogas; a mixture of CO2 and methane. This biogas is converted into heat and electricity which is injected directly into the National Grid to power homes and businesses, rather than releasing them into the atmosphere. This activity is a unique example of how UK businesses can help remove greenhouse gases from the atmosphere (and reduce fossil fuel reliance, thus decreasing emissions) through a natural, biological process, repurposing them to benefit the economy and nation.
This process also produces a solid called biofertiliser, or digestate. This is a nutrient-rich substance that can be applied to farmland to boost crop growth. The benefit of this by-product is its ability to reduce the need for artificial fertilizers, many of which are made using fossil fuels.