What is climate change: a guide to its causes, effects and solutions

18 November 2020 | Celia Topping

Climate change is happening right now, as you’re reading this. It’s a crisis that affects our whole planet and everyone on it. We stand at a crucial moment in history – and there’s still time to do something about it. This is our opportunity. Let’s grab it! But first things first...

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What’s the difference between climate change and global warming?

A very good question. These terms are often used interchangeably, but in fact are quite different:

  • Climate change refers to both human and naturally-produced warming, and the effects it has on our planet. It’s a long-term change in the average weather patterns that have come to define Earth’s local, regional and global climates. 
  • Global warming is the long-term heating of Earth’s climate system observed since the pre-industrial period due to human activities, primarily fossil fuel burning.

So what is the greenhouse effect?

When sunlight hits the earth, about 30% of solar energy is reflected back into space. The other 70% gets absorbed by our oceans and land, which also radiate heat into the atmosphere.

There are naturally-occurring greenhouse gases in our atmosphere − such as carbon dioxide. These gases absorb the heat and radiate it back out again, like tiny microscopic heaters − acting as a blanket, keeping the earth warm. This is known as ‘the greenhouse effect’. Without the greenhouse effect, the earth's average surface temperature would be -18°C. Pretty chilly! Instead, today it’s a rather pleasant 15°C. That means greenhouse gases (such as carbon dioxide) make life on Earth possible. 

If carbon dioxide isn’t all bad, what’s the problem?

Well, the issue is how much carbon is being released into our atmosphere − and how fast. This has upset the delicate balance of what we call the earth’s ‘carbon cycle’.

Carbon takes many different forms as it moves between plants, animals, soil, oceans, and the air, via processes like photosynthesis and respiration. Nature keeps everything in balance, by taking carbon dioxide out of the air, thanks to the trees and the plants. The water in the oceans dissolves carbon dioxide too. 

This is our natural carbon cycle − and it's one which exists in a state of dynamic equilibrium. So many processes on the planet are constantly rebalancing the amount of carbon. It’s nature's way of recycling carbon atoms, using them again and again to become all kinds of things.  

Learn the difference between "carbon neutral", "zero carbon", and "net zero" by reading our useful guide.

Causes of climate change

For thousands of years, the Earth’s carbon cycle was perfectly balanced, and the levels of carbon dioxide in the atmosphere stayed almost the same. In fact, the concentration of carbon dioxide in Earth’s atmosphere was stable for 800,000 years! But then, in the late 18th century, the Industrial Revolution happened and carbon levels began to climb. Since then, they’ve risen over 40%1.

We know that it’s humans who are causing this. And it’s mainly down to us burning fossil fuels like coal, oil, and gas. When these are burned they release a lot of energy. That’s why humans have used them to power modern society.

But they also release lots of carbon dioxide into the atmosphere. And we’re burning them more and more, causing carbon dioxide concentrations to increase 100 times faster than the natural rate. Half of all the carbon emissions released since 1751 have occurred in the past 30 years!

We’re also responsible for two other causes of climate change:

  • Agriculture – large-scale farming releases large amounts of nitrous oxide and methane, two powerful GHGs. Methane is released by livestock when they pass wind – which they can do a lot –  and also by their manure. And widespread use of fertiliser has resulted in a dramatic rise in nitrous oxide, the third most potent greenhouse gas after carbon dioxide and methane.
  • Deforestation – trees are nature’s best way of absorbing carbon emissions from the atmosphere. But farming is causing vast deforestation. Not only does cutting down trees mean less absorption, but they also release the carbon they’ve absorbed when they're removed. Double the reason to not chop down our carbon-munching friends.

Climate change: the facts

what is climate change

It’s difficult to ignore the scientific facts, no matter what climate-deniers say. The Intergovernmental Panel on Climate Change (IPCC) was set up in 1988 to give objective scientific information on climate change, its causes, impacts, future risks, and possible solutions. Since then they’ve written several reports, all with the same conclusion: “climate change is real and human activities are the main cause.” 

The world has already warmed by 1°C since pre-Industrial times – and that’s down to human activity. If this carries on, the temperature would pass 1.5°C between 2030 and 2052. 

Why is 1.5 degrees celsius so important?

Scientists tell us that the global temperature rise must be kept below 1.5°C to avoid the worst impacts of climate change. Even a rise of above just 2 degrees would have catastrophic consequences. 

The 1.5°C target could2:

  • Prevent small island states and coastal areas and cities from being swallowed by the ocean. (Sea levels are expected to rise 10cm higher this century under 2°C of warming. That could expose an extra 10 million people to impacts like flooding, and saltwater getting into their fields and drinking-water).
  • Help millions of people avoid the disasters of extreme weather, such as drought, hurricanes, flooding and wildfires. 
  • Limit the chances of an ice-free Arctic in the Summer. A rise of 2°C would virtually wipe out coral reefs, compared to a 70-90% decline at 1.5°C.
  • Stop loss of biodiversity: out of 105,000 species studied, the rate doubles between 1.5 and 2°C of warming. 
  • An estimated 1.5 - 2.5 million square kilometres more permafrost would thaw this century with 2°C of warming, compared to 1.5°C (that’s the equivalent to the size of Mexico). Thawing permafrost also releases methane, a toxic greenhouse gas, and the vicious circle continues.

How hot can it get?

A leading scientist at Carnegie Institute for Science, Dr Ken Caldeira, says that if emissions continue without check as they have been, “there is a 93% chance that global warming will exceed 4 degrees celsius by the end of this century”. The IPCC’s ‘worse-case scenario’ even goes as far to say that 5°C could be reached. Which really is game over for planet Earth as we know it. 

What are the effects of global climate change?

This image illustrates some of the drivers of climate change and the impacts they could have on the climate system (Met Office UK).

Mother Earth has seen plenty of fluctuations between tropical climates and ice ages throughout her 4.5-billion-year history. But Earth’s average temperature is now rising unnaturally. There are serious environmental and social knock-on effects – including changing weather patterns, melting ice caps, rising sea levels and mass migration. The higher the temperature increase, the worse the impact on the planet. 

All this is bad news. But we must remember, Earth will survive, as it always has. The physical impacts mentioned above only seriously affect everyone living on the Earth, not the Earth itself. It’s humans (and animals) who can’t adapt quickly enough. Mother Earth will still be turning long after we’ve caused our own extinction. A sobering thought. 

Extreme weather events

As the Earth heats up, ice caps melt,  sea levels rise and rainfall increases. In turn, these cause extremes in weather – from floods, hurricanes and cyclones, to heatwaves, droughts and wildfires. Here are just a few global examples of how climate change is affecting our weather: 

UK – flooding

2019 and 2020 saw many rivers reach their highest levels on record, causing devastating floods across England and Wales. Floods are made more likely by extreme weather patterns linked to long-term climate change. And when vegetation is cleared, those changes in land cover also increase the risk of flooding.

Read our complete guide to protecting your home against flooding and extreme weather

Western Europe – heatwaves

It’s official. On average, the world’s temperature has risen by about 1°C since pre-industrial times. It doesn’t sound like much, but we’re feeling the heat. The 10 years to the end of 2019 have actually been the hottest decade on record, with temperatures above 40°C in Belgium and the Netherlands, for the first time ever. Experts say these extreme heatwaves are now 10 times more likely to happen, all because of the climate crisis.

California – wildfires

A dangerous combination of heatwaves, dry vegetation, and more lightning strikes has caused years of ferocious, lethal wildfires in California. Scientists say the situation has been made far worse by climate change.

Central America – hurricanes

Scientific analysis tells us that hurricanes have become stronger worldwide over the past 4 decades. Climate change is making these storms even more destructive. 

By the way, if you've ever wondered why us Brits are so obsessed with the weather, learn all the intriguing answers in our blog.

Health risks

The 4 pillars of good health are clean air, safe drinking water, nutritious food and shelter. All of these are affected by climate change, as well as causing rising infection rates from diseases and viruses:

  • Spread of pests and diseasesdeforestation creates favourable conditions for mosquitoes, so malaria, dengue fever and zika are on the rise. For example, in Ethiopia, areas troubled by malaria have grown since the climate has warmed up. 40 years ago, you wouldn’t find a single case of malaria in the highlands. But, today, outbreaks there are common. This is because climate change has made it hotter at night, allowing malaria-infected mosquitoes to live at altitudes where they couldn’t survive before. 
  • The risk of pandemics such as Covid-19 and bird flu is much higher, due to wild places being destroyed for farming and trade. And that brings humans into contact with unknown dangerous microbes.
  • Lack of fresh, clean water – caused by droughts. And ironically, heavy rainfall can cause cholera and diarrhoea outbreaks, due to water sources getting contaminated.
  • Reduced food supply/agricultural yields – extreme weather destroys crops. This leads to a huge impact on the global food supply, leading to malnutrition and even starvation. For example, parts of Africa are facing long droughts that damage food crops. In Zimbabwe, for several years, the rainy season has been getting later and shorter, ruining the traditional farming cycle. In 2019, the harvest was catastrophic for the second year running, with up to 70% of crops lost. The World Food Programme says that 60% of Zimbabwe's 15 million people are now in danger of going hungry.
  • Lack of shelter – caused by storms, hurricanes and droughts. For example, there are over a million displaced climate refugees in Somalia, forced from their homes by drought in the past few years. “Many remain in a protracted state of displacement,” says the United Nations Refugee Agency3

The World Health Organisation (WHO) estimates around 250,000 deaths will be caused by climate-sensitive diseases between 2030 and 2050. 

Impact on the ocean

climate change effects

Did you know that over 70 percent of the world’s surface is ocean? As explained above, the ocean naturally absorbs the heat of the sun, and also some emissions. But with the unnaturally-quick rise in carbon emissions and temperatures caused by us, there are dangerous knock-on effects: 

  • Rising sea levels. With the speed Arctic ice is melting, by 2100 the ocean could have risen one to four feet. This could mean catastrophic flooding in low-lying and coastal areas, affecting 190 million people. Major cities such as New York, Rio de Janeiro, Mumbai and Sydney would be affected. 
  • Rising ocean temperatures. Water expands as it warms, also contributing to flooding. Warmer oceans also cause coral bleaching and irreversible damage to underwater ecosystems.
  • Ocean acidification. Scientists reckon around a quarter to a third of the carbon we emit is absorbed by the ocean. This makes the ocean more acidic, causing a devastating impact on marine life.
  • Ocean warming causes red algae blooms, which kill fish and animals, and can also cause illness in humans.
  • Released toxic gas. Thawing ice in the Arctic releases vast quantities of methane, a toxic GHG, adding to the greenhouse effect. 

Danger to ecosystems

Due to climate change, wildlife tries to adapt in a few different ways. This includes changing migration patterns and seasonal behaviour. In turn, these shifts have effects through entire ecosystems, impacting biodiversity. It’s estimated that a quarter of mammals, a fifth of reptiles, a sixth of birds, and a third of marine life are heading towards total extinction.  

Take, for instance, the Asian elephant. Lower rainfall and higher temperatures are damaging its habitat. There are a number of reasons why these elephants are vulnerable to a changing climate. They’re sensitive to high temperatures.

They’re also prone to disease, so they’re easily affected by altered disease patterns caused by the climate crisis. The plants they like to eat are also being driven out by invasive species, which have taken over with changing conditions. The result? Falling birth rates for a species already in danger of dying out.

Can we slow down climate change?

This is a critical decade for action on climate change. It's not too late. We have a chance to take action and prevent the worst impacts of climate change.  If we act now, climate change can be slowed, or even paused – to an extent. Though even this would require dramatic action everywhere, by everyone, right now. 

It's also important to know how much damage is being done to the environment through food waste. It creates 6 times the carbon emissions as global aviation! Find out more about how food waste is damaging the environment and what we can do to stop it in our new blog. 

What is being done to combat climate change?

In 2015 in Paris, all 195 members of The United Nations Framework Convention on Climate Change made the momentous agreement to keep global temperatures well below 2°C. By 2018, UN scientists revealed what a huge difference it would make to keep temperatures at 1.5°C (see above). 

Following the Paris Agreement, the United Kingdom became the first country to commit to net zero by 2050. Then suddenly, in 2020, a flurry of countries followed suit, including Japan, South Korea and most importantly, China. The world’s biggest emitter of carbon dioxide now aims to hit peak carbon emissions by 2030 and be carbon neutral by 2060.

With the election of Joe Biden came a promise to reverse President Trump’s withdrawal from the Paris Agreement, and also be net zero by 2050. This means the economies producing more than half of the global carbon emissions have publicly made this critical pledge. 

Because of these pivotal promises, fossil fuel is fast becoming a dirty word and change is being seen the world over:

  • Fossil fuel divestment (meaning the opposite of investing in fossil fuels)
  • Legal cases being brought against fossil fuel companies/governments
  • Renewable energy becoming cheaper than fossil fuels
  • Businesses driving an innovative ‘circular’, rather than linear, economy (stopping waste and keeping resources in use as long as possible)
  • Veganism on the rise 

Of course, the point is that climate change can’t be solved by just one person or group – everyone needs to take up the cause. Governments, businesses, investors and individuals. So let’s change the way we live, move towards zero carbon living, and encourage others to do the same. 

What can I do to help stop climate change?

We all know about that 15-year-old girl who one day took a stand outside Swedish Parliament and became a globally-recognised environmental activist. Her Fridays for the Future movement mobilised over 13 million people across 7,500 cities worldwide. We can’t all be a Greta Thunberg. But we can make small, simple shifts in our everyday lives to reduce our carbon footprint and help stop climate change. 

Reducing carbon emissions and using green energy is the way forward – so how do you go about it? 

Let’s start at home

Refuse, reuse, reduce and recycle

Watch what you eat

  • Cut out, or at least cut down on red meat. It makes a mind-boggling difference.
  • UK homes waste 4.5 m tonnes of food a year. Try to only buy what you need and pickle, preserve, freeze or compost what you don’t eat.
  • Try rice, oat or almond milk instead of dairy – it’s way more eco-friendly.
  • Buy locally-sourced seasonal food. It saves on emissions from transportation, preservation and refrigeration (and it tastes better!).
  • Get inspired for veggie meals with BBC Earth host Max La Manna, and his delicious #moreplantslesswaste recipe ideas.

Start a climate conversation

Talk to your bank

  • Find out if your bank invests your money in fossil fuel. If they do, ask if you can opt out.
  • Moving your pension to a more sustainable fund can have more impact on reducing your carbon footprint than giving up flying and becoming a vegan put together!
  • Choose an ethical bank that focuses on socially responsible investment and has a positive impact on our world.

OVO’s commitment to sustainability

At OVO, we’re leading by example and putting action on climate change at the centre of our business. Our purpose is to drive progress to zero carbon living.  

In 2019, we launched our mission to make zero-carbon living a reality, which means becoming a net zero carbon business and helping our members become more sustainable too.

Want to help stop climate change? Choose a renewable home energy plan. We include hydro power, wind power and solar power in our fuel mix. 

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