Climate change: The basics

Climate change describes the long-term changes to the global temperature and weather patterns. The world’s climate has continually and cyclically changed since the very beginning, but human activities like burning fossil fuels, deforestation, agriculture and manufacturing are making that change happen at a much faster rate. 

Our earth is 1.1°C warmer than it was in the 1800s (or pre-industrial times), with the last ten years being the warmest so far. Here in the UK the most recent decade has seen temperatures around 0.8°C warmer that the average from 1961-1990; all ten of the warmest ever years in the UK have happened since 1990.

But why are we so concerned about this seemingly small change in temperature – doesn’t the temperature fluctuate by this magnitude on a daily basis?  The difference is that these fluctuations are local, predictable, and cyclical events, whereas the global temperature (as shown in the chart above) depends on how much energy our planet receives from the sun and how much is emitted back into space. This incoming energy from the sun remains largely the same year after year, which means that change in global temperatures is mainly due to changes in Earth’s responses and systems. Read on to know more about what is causing these changes in the Earth’s responses.

The 1˚ global temperature increase mentioned earlier is quite significant, because it takes a vast amount of energy to heat up our oceans, land and atmosphere by this amount. In the past a 1˚to 2˚ drop was all it took to plunge the Earth into the Little Ice Age. We might think of this warming as only affecting the atmosphere, but most of climate change is happening in the ocean. 

Around 90% of the heat produced goes into the ocean. This directly affects sea levels as warmer water expands, increasing flooding and destructive weather events like hurricanes, while also destroying the finely balanced biodiversity in our seas. More effects of unchecked climate change are well documented and seen all around us: warming, flooding, fire, drought, more damaging and unpredictable weather patterns and the destruction of our ecosystem. 

The UK Met Office says that “2022 was a record-breaking year for weather and is a sign of the UK’s changing climate.” 2023 then followed as the second warmest year on record.

Deforestation only worsens this situation, as not only does it reduce the amount of trees available to absorb carbon dioxide, but cutting them down and burning them releases the carbon they have absorbed back into the atmosphere as carbon dioxide.

The above-mentioned changes are having a very real and direct impact on people around the world; their homes, businesses and futures, some of which are increasingly evident when we turn on the news. Whether the resulting impacts are as extreme as famine or, at the other end of the scale,  simply having to pay more to protect our homes from flooding, the effects of climate change will touch each and every one of us.

Scientists are in agreement that human activity is responsible for the climate crisis we see today, but as it is being caused by us, we should be able to do something about it too. The Paris Agreement, which was adopted back in 2015 by 196 countries, stated that limiting the average global temperature increase to 1.5°C (compared to pre-industrial levels) before the end of this century, this would slow down or even mitigate the worst impacts of climate change. 

To get to this number, there needs to be a worldwide reduction of 48% in carbon emissions by 2030 (compared to 2019), reaching net zero by 2050. Net zero means that the “greenhouse gases going into the atmosphere are balanced by their removal out of the atmosphere”. Reaching the 1.5°C target depends on the global response from governments on how to Iimit greenhouse gas emissions. 

Climate change has been recognised as an issue of concern since the last century, but collective actions by  governments from all over the world is a more recent phenomenon. Some most notable milestones by the United Nations (representing 193 member countries) include- 

Montreal protocol 1987 – Ratified by every country in the world to stop producing Chlorofluorocarbons (CFCs) to prevent damage to the ozone layer 

UN framework Convention on Climate Change 1992 – The first global agreement to directly deal with climate change which established the Conference of Parties (COP) for international discussions on dealing with greenhouse gases 

Kyoto Protocol 2005 – The first legally binding climate treaty where countries were required to reduce emissions. Major carbon producers wouldn’t act on it including the USA who retracted their signature

Paris Agreement 2015 – The most significant global agreement where a commitment was made to keep the average global temperature rise 1.5°C and an ambition of net zero emissions was set. It required all countries to set reduction limits which are assessed by each country every five years. These interim targets are known as Nationally Determined Contributions (NDCs), which feed into Long-Term Strategies (LTS). By early 2025, countries are scheduled to unveil their new national climate commitments under the Paris Agreement. 

Glasgow Climate Pact 2021 – The first climate agreement explicitly planning to reduce unabated coal, i.e. where the carbon produced by burning coal is released into the atmosphere. 

As part of the UK’s commitment to meeting its net zero target by 2050 (Scotland’s net zero commitments are different), the government has committed to a number of key policies, which include:

• Decarbonising electricity generation by 2030 
• An end to the sale of new diesel and petrol cars and vans by 2030
• Tighter minimum energy efficiency standards for homes and commercial buildings
• Financial support for households to improve energy efficiency and install low carbon heating systems
• A particular funding focus on decarbonising social housing and households on lower incomes in energy inefficient buildings
• Investment in Carbon Capture and Storage and hydrogen production
• Establishing three new National Forests in England and planting “millions of trees”