Confused about climate and Cop26? This jargon buster should help

World leaders meeting in Glasgow for the UN Cop26 summit are under pressure to take action on climate change – but what exactly is it they are talking about?

Here are some of the commonly used climate terms and what they mean.

– Greenhouse gases

These are gases that trap some of the heat from the sun in the atmosphere and keep the planet warm enough for life to thrive.

Concentrations of these gases – which include carbon dioxide, methane and nitrous oxide – have increased at a rapid rate in recent years.

– Greenhouse gas or carbon emissions

This is the release of greenhouse gases, particularly carbon dioxide, into the atmosphere, mainly from burning fossil fuels – coal, gas and oil – in things such as power stations, vehicle engines and boilers for heating buildings.

Livestock and changes to how we use land, including cutting down or burning forests and draining peatland, industrial processes such as cement making and refrigerants are among other sources of greenhouse gas emissions caused by human activity.

– Global warming

Because of emissions from human activity, the overall level or concentration of carbon dioxide and other greenhouse gases in the atmosphere has increased.

The higher the concentrations in the atmosphere, the more they trap heat and warm the Earth, pushing up temperatures across the land and oceans, which is known as global warming.

In 2020, global temperatures were around 1.2C above what they were in the 19th century, before most of the industrial activity driving emissions got going.

– Climate change

This encompasses the rapid changes we are seeing to weather conditions and the natural world, driven by global warming and the human activities that cause it.

Impacts we are already seeing include more frequent and extreme heatwaves and wildfires, increased rainfall and storms which can cause floods, melting ice and rising sea levels, changes to crop yields and loss of wildlife.

As temperatures continue to rise, the impacts of climate change are projected to worsen, and the situation is increasingly being referred to as a climate crisis or emergency.

– Net zero

Cutting greenhouse gas emissions from human activity to zero overall, which is needed to halt the global temperature rises driven by the increase in levels of gases in the atmosphere.

Just as you need to turn off a tap completely to stop the level of water in a bath from continuing to rise, we need to cut emissions to zero to stop the greenhouse gas levels – and therefore temperatures – rising.

Completely stopping emissions is extremely difficult, but there are some measures, such as planting trees, which can absorb greenhouse gases from the atmosphere – the equivalent of bailing some water out of the bath to keep the water level steady even if the tap is still running slightly.

So emissions have to be cut as much as possible, and any remaining pollution, from hard-to-tackle sectors such as aviation, needs to be “offset” by action that absorbs carbon to have the net effect of cutting emissions to zero.

– Decarbonisation

The process of removing the emissions associated with activities or sectors, for example decarbonising electricity generation by phasing out coal and gas plants that put out pollution, and building renewables such as offshore wind farms.

– Paris Agreement

The world’s first comprehensive treaty on climate change, agreed under the United Nations in the French capital in December 2015.

Under the deal, all countries commit to action to limit temperature rises to “well below” 2C above pre-industrial levels and pursue efforts to keep them to 1.5C, to reduce the risks and impacts of climate change.

– Nationally determined contributions (NDCs)

National plans for climate action submitted by countries under the Paris Agreement, which outline post-2020 action to tackle climate change, with many plans running to 2030.

Cop26 is the deadline for new, more ambitious NDCs under a five-year process established by the Paris deal, with current policies and plans leaving the world way off track to meet the 2C or 1.5C goals.

– Cop26

This is the latest global climate summit held under the UN’s climate change convention, which is being hosted by the UK and taking place in Glasgow.

Cop26, delayed from last year by the pandemic, is seen as the most important international climate meeting since Paris 2015, because it is the NDC deadline and has been described as the last best chance to keep 1.5C in reach.

There will also be negotiations to agree the final parts of the “rulebook” for implementing the Paris Agreement, and talks focusing on finance to help countries cope with the impacts of climate change.

Cop stands for “conference of the parties”, and this is the 26th one held under the convention, usually annually since 1995.

– AOSIS, LULUCF, YOUNGO and more…

These are just some of acronyms and jargon that surrounds the UN convention – which is known as the United Framework Convention on Climate Change or UNFCCC.

There are country groupings such as AOSIS, or the Alliance of Small Island States, areas of climate action, such as LULUCF or land use, land use change and forestry, and representative groups including children and young people – known as YOUNGO.