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Buzzwords like ‘net zero’, ‘carbon neutral’ and ‘mitigation’ often sit centre stage in headlines but what do they actually mean? Here we untangle some of the most common phrases used in climate change reporting and discussions.
Fossil fuels refer to a group of energy sources, mainly coal, oil, and natural gas. They are formed from the remains of ancient plants and animals that absorbed carbon from the atmosphere during their lifespan. After death, they decomposed and were compressed under layers of rock over millions of years. Separated into basic states of matter, they form fuel such as coal, petroleum, or natural gas. Because fossil fuels take millions of years to form and are finite in supply, they are known as non-renewable sources of energy.
Fossil fuels are our main global energy source, used to power modern life – including for heating, electricity, machinery, and transport. Burning these fuels releases the trapped carbon back into the atmosphere. Our over-reliance on fossil fuels is a major cause of climate change, particularly global warming.
This refers to a group of gases that provide the atmospheric conditions that contribute to regulating our climate. Carbon dioxide, water vapour, methane, and nitrous oxides are among the main greenhouse gases. They act like a greenhouse surrounding the Earth, making our planet warm and habitable. However, human activity has rapidly changed the composition of greenhouse gases in our atmosphere, making the Earth hotter and the climate unstable.
The natural greenhouse effect is the way that greenhouse gases trap heat close to the Earth’s surface. It operates like an insulating blanket wrapped around the planet, keeping us warm and moderating our climate. For millions of years, greenhouse gases have trapped just the right amount of heat to allow life to thrive; without them, it is estimated that the average global temperature would be in the region of -18C.
However, from the onset of industrialisation, we have been releasing heat-trapping greenhouse gases into the atmosphere at a rate that has altered the natural balance. This man-made greenhouse effect is tipping the planet towards increased warming and is driving climate change.
Put simply, a tipping point is a point of no return where change becomes inevitable. It’s a term often used in relation to critical climate thresholds that, once passed, would lead to harmful and irreparable changes. The stability of our planetary systems – our land, atmosphere and oceans – would be severely affected, with serious repercussions for humanity.
For example, global heating (an increase in average temperatures) of even 2 degrees Celsius would cause irreversible melting of the ice caps, an associated rise in sea levels, and more extreme weather cycles.
Tipping points are identified by scientists who predict what would happen if such thresholds are crossed, highlighting the urgent need for us to act now to prevent further damage – before it’s too late.
There can be positive tipping points, too – in the battle against climate change. Cheaper, more efficient car batteries, leading to the wholesale adoption of electric cars would represent a positive tipping point in relation to climate change.1
The carbon cycle is a key process on Earth; carbon flows from the atmosphere to the land or ocean and back again. All living things contain some form of carbon and our planet continuously recycles it in multiple ways, from volcanic eruptions to photosynthesis. An effective carbon cycle helps to regulate the climate because it balances how much carbon is in any one place.
Climate change, including rising global temperatures, is a symptom of an unbalanced carbon cycle. We’ve disrupted it by mining and burning fossil fuels at a rate too fast for nature to reclaim the carbon that is released. We can help restore the balance by keeping fossil fuels in the ground and instead choosing to rely on clean, renewable energy sources such as solar and wind power.2
In simple terms, biodiversity refers to the incredibly rich variety of life on Earth. It’s a contraction of “biological diversity” and encompasses every living organism, including microbes, bacteria, fungus, insects, plants, and animals.
The interaction between all life forms a complex web of balanced dependencies. Removing any of these strands will destabilise the network, locally and as a whole. Human activity, the repurposing of land, and climate change have weakened our planet’s biodiversity, posing a threat to the natural world and to us.
Rewilding land, reintroducing native plant and animal species, sustainable fishing, restoring coral reefs, pollution management, and new planning laws are attempts being made to restore biodiversity.3
Permafrost is ground that has been permanently frozen for at least two years – in some cases for thousands of years. It’s often hidden below the surface, and can range from 1m to 1km in thickness. It’s found in the colder regions of the northern hemisphere, from China’s Tibetan Plateau to the Arctic, where it even exists below the ocean floor.
Much of our planet’s permafrost is melting, or thawing, due to climate change. As the ground softens, it’s causing harmful effects and disrupting the way of life for the five million people who live in these areas. Buildings have succumbed to unstable foundations, and landslides have swept through towns and villages. Not only this, but captured in the permafrost are large volumes of methane and carbon dioxide; greenhouse gases that if released into the atmosphere will further accelerate the rate of global warming.
Keeping average global temperatures from rising any more will help to prevent permafrost from melting past a tipping point.4
The term climate anxiety, or eco-anxiety, explains the feelings of distress or fear that people are experiencing in response to the threats posed by climate change. As we increasingly see images and hear news stories about the future, it’s understandable this has become a widening trend. A global study by Bath University that looked into the thoughts and feelings of young people revealed that more than 59% were extremely worried about the future, and 83% think that we have failed to take care of the planet.5
As an antidote to feelings of doom and gloom, climate optimism is a global movement that looks to harness the energy we feel through climate anxiety and turn it into positive action.
Indigenous knowledge is a term that refers to the collective wisdom and understanding of nature’s cycle by people who have lived in balance with the Earth for generations. Using natural resources sustainably is a way of life for indigenous cultures – communities that protect a significant area of our planet’s richest natural landscapes.6
Indigenous peoples make up 5% of the world’s population yet they protect 80% of the world’s biodiversity.7 These communities are often on the front lines of climate change, and their observations are giving scientists valuable insights into certain climatic changes and shifts in nature’s rhythms.
Carbon sinks absorb or remove more carbon from the atmosphere than they release. The ocean, forests, and soil are all effective carbon sinks that store carbon as a part of the carbon cycle.8
Because they draw carbon from the atmosphere, carbon sinks are a natural defence against the worsening effects of climate change. They can play a significant part in balancing the carbon cycle, so maintaining and protecting them should be a priority in our efforts to tackle the problem. Reducing deforestation, promoting healthy soil and minimising pollution in our oceans will optimise the work of carbon sinks in keeping our atmosphere stable.
This is the dirty stuff: the release of greenhouse gases into the atmosphere by various activities, including transport, building, manufacturing, and farming.
Emissions created by humans have risen in volume since the beginning of the Industrial Revolution. This rise is directly responsible for climate change and its effects, from drought and wildfires to flooding and more frequent and intense storms.
This means ways to prevent climate change from getting worse, most importantly by reducing the amount of greenhouse gases we release into the atmosphere.
Mitigation options include switching to solar or wind energy, enhancing and protecting carbon sinks, eating less meat, using greener modes of transport, and limiting the amount of waste we produce. The small actions we all take – as well as the large ones – have a cumulative effect and can help tip the balance in our favour, helping protect the planet and ensure its habitability for future generations.9
Both terms refer to the balancing of greenhouse emissions; removing from the atmosphere the same amount that has been released. These two terms are often used interchangeably, but according to the UN’s Intergovernmental Panel on Climate Change (IPCC), they mean the same thing on a global scale, but there’s a subtle difference when it comes to a regional, national, and sub-national level. Using this definition, ‘net-zero CO2’ usually applies to emissions that are the responsibility of a country, district or sector, while ‘carbon neutral’ is related to business activity such as manufacturing or events.
To pave the way to a habitable, healthy planet for generations to come, the 2015 Paris Agreement, a treaty signed by 194 countries, says our planet ‘needs emissions to be reduced by 45% by 2030, and reach net zero by 2050’. 10, 11
This term refers to transformative changes to our lives and global systems on a scale that has never been seen before, to make the most difference towards a cleaner, healthier planet. Reshaping our energy systems so the world is only powered by clean and renewable sources such as solar and wind is a prime unprecedented transition. It is believed that these necessary shifts could filter through to many sectors of how we live, such as reshaping the global economy, or rethinking how we design cities so that the health of our planet – and ourselves – always comes first.
According to the IPCC, ‘limiting global warming to 1.5C will require “unprecedented transitions”’. There are also other benefits to these necessary shifts, like our general well-being and mental health, a more equal society, and – just as important – a secure future for the next generations.12
For more stories about the themes explored here, take a look at the #OurFrozenPlanet campaign across BBC Earth.
#OurFrozenPlanet is a digital initiative from BBC Earth in association with The Moondance Foundation, bringing you urgent stories about the effects of climate change around the globe, and accounts of the people dedicated to championing positive change to protect the future of our planet.
1. Tipping point, 2. Carbon Cycle IPCC Glossary , 3. Biodiversity - IPCC Glossary 4. Permafrost - IPCC Glossary , 5. Climate anxiety in children and young people, 6. Indigenous knowledge and climate resilience , 7. Indigenous people protect 80% of the world’s biodiversity. 8. IPCC glossary - carbon neutral and net zero , 9. Mitigation - IPCC Glossary , 10. IPCC glossary - carbon neutral and net zero , 11. The difference between net zero and carbon neutral , 12. The IPCC definition for transition