Climate change is sustained alteration of the Earth's weather patterns over a long period of time. Global emissions of greenhouse gases such as carbon dioxide (CO2) accelerate climate change.
The surface of the Earth has cooled and warmed as it shifts in its orbit around the sun throughout millennia. But average global temperatures have risen rapidly since the middle of the 20th century: the ten hottest years on record have all occurred since 2000, and 2014 was the warmest since 1880. Arguments persist as to whether this is a natural event – but strong evidence suggests that human activity is having a dramatic impact.
Generating electricity, deforestation, agriculture, industrial processes, driving cars and air travel have all increased levels of greenhouse gases – strengthening the greenhouse effect and causing global temperatures to rise.
If global temperatures rise by only 2°C, as many as 30% of the Earth's species could face extinction. The likelihood of extreme weather events, including heatwaves, flooding and drought will increase. Rising sea levels could inundate islands and coastal areas, seriously affecting agriculture and food security.
Tackling climate change poses an enormous challenge to industrialised countries – responsible for most CO2 emissions – and to developing economies, where energy demands are predicted to increase significantly.
Generating electricity is one of the biggest contributors to greenhouse gas emissions worldwide. Curbing emissions of CO2 and other greenhouse gases will require huge changes in how we produce and use energy in the future.
To meet its carbon-reduction commitments, the UK must phase out the use of carbon-rich fuels to generate electricity. The UK Government advises that 40% of our electricity should come from low-carbon energy sources by 2020, while the Committee on Climate Change proposes that almost all UK electricity should come from low-carbon sources by 2030.
What is being done?
Climate change is high on the international agenda, and governments, industry and the public each has a part to play in tackling it. We need to transform how we live – both as individuals and as societies.
Much of the world's carbon dioxide emissions come from the generation and use of energy. We can reduce these emissions in three main ways:
- Use energy more efficiently.
- Reduce the impact of energy production.
- Use alternative sources of energy.
The energy industry has a significant role in reducing emissions: by switching to renewable energy sources such as wind and solar, and low-carbon sources like nuclear. They can also advise their customers on how to be more energy efficient.
Energy companies are developing new ways to generate energy from wind, wave and tide. Where fossil fuels are burned, Carbon Capture and Storage (CCS) technology can prevent emissions from entering the atmosphere. Electricity grids must be connected to greater numbers of renewable energy sources if climate change targets are to be met.
The drive to cut carbon emissions has become a key goal for many of the world's largest companies, who are working to find ways of making their operations more energy efficient. For example, the transport sector is developing hybrid and electric road vehicles, and researching non-fossil aviation fuels.
What does it mean for the UK?
The UK is responsible for about 2% of global CO2 emissions. The energy sector contributes the largest share, at 33.4%. Road transport accounts for 19%, residential and business emissions account for 29.7%, and agriculture accounts for 9.5%, according to government statistics.
The Committee on Climate Change suggests we may experience rising sea levels and more extreme weather events such as flooding and heatwaves. During the heatwave of 2003, when average summer temperatures were 2°C higher than normal, there were more than 2,000 additional deaths in the UK.
In an extreme and prolonged heatwave, road surfaces could melt and rail lines buckle, causing disruption to our transport network. Storm surges might threaten coastal railway lines and roads. Climate change could hasten the spread of animal diseases – exposing the country to a new or increased risk of infection.
Implications for the energy industry are a greater demand for electricity in the summer, to power more air conditioning units as householders and office workers try to keep cool. Increased risk of flooding from heavy rain is already prompting water companies to consider adapting their drainage systems to cope with much larger volumes of rainfall.
How is the UK responding?
With the Climate Change Act 2008, the UK became the first country in the world to propose a long-term strategy to cut carbon dioxide emissions. As a result of this, the following measures have been introduced:
- Emissions target of 80% below 1990 levels by 2050
- Interim target of reduced emissions of at least 35% by 2020
- 5-yearly carbon budgets to ensure these targets are met
To meet the fourth carbon budget (2023–2027), the UK must cut greenhouse gas emissions to 50% below 1990 levels by 2025.
Published in 2013, 2050 Pathways outlines the choices the UK must make during the next 40 years – showing that we can meet both the 80% emissions reduction target and our growing demand for energy.
The UK Government recognises that future energy strategy must combine:
- Greater energy efficiency
- Reduction in carbon emissions from fossil fuels
- Expansion of low-carbon power
- Increased use of low-carbon electricity
All EU member states have signed up to the Renewable Energy Directive 2009, which commits the UK to producing 15% of our energy from renewables by 2020.
The UK is developing Carbon Capture and Storage (CCS) technology, which could cut dramatically the amount of CO2 fossil fuel power stations release into the atmosphere. Biomass, biogas and small-scale wind turbines will also have a role to play alongside large-scale power stations. Overhauling the electricity grid could cut emissions by allowing new renewables and other low-carbon energy sources to connect more quickly.
Switching to a low-carbon economy will not be cheap – but the UK Government believes it will prove its value in the long term. Businesses that cut their carbon emissions will save money on energy bills and production costs, and benefit from new economic opportunities.
In 2009, more than 15% of UK CO2 emissions came from households. The level of emissions generated directly by households had remained broadly constant at around 140 - 160 Mt CO2e but dropped in 2011 to 134 Mt CO2e, before rising to 142 Mt CO2e in 2012 (due to 2012 being a colder year). So we can say that the UK household emissions have remained at around 16%. We can all reduce these emissions – by using energy-saving light bulbs, turning our central heating down by 1°C, and switching off lights in empty rooms. Reducing emissions will also reduce our energy costs.
No energy comes without a carbon cost, even if – like wind, sun and water – it appears to be free. How exactly an energy source contributes to climate change is measured by calculating carbon emissions over its lifetime.