Causes of climate change

Climate change is happening because of us.

Human activities are releasing excessive amounts of greenhouse gases into our atmosphere.

As a result, the globe is already one degree warmer on average than it was before the Industrial Revolution.

© Edward Parker / WWF


As concentrations of greenhouse gases have increased, the Earth has warmed

From 1906-2005, the average global temperature rose by 0.74ºC, with most of that warming occurring since 1970. By 2015, the average global temperature had warmed by over 1ºC since pre-industrial times. Sixteen of the 17 warmest years on record have been in 21st century.

This warming isn't the same everywhere. Some areas with crucial ecological importance - like around the poles - are warming at two or three times the global average. 

This climate change is because of human activity

The main causes of climate change are: 

  • Humanity’s increased use of fossil fuels – such as coal, oil and gas to generate electricity, run cars and other forms of transport, and power manufacturing and industry

  • Deforestation – because living trees absorb and store carbon dioxide

  • Increasingly intensive agriculture – which emits greenhouse gases like methane and nitrous oxide

Today's industrialised countries – includng New Zealand – have built their economies on buring fossil fuels to provide electricity, transport and to develop industries. Developing countries are now beginning to do the same. 

New Zealanders are big emitters

Though Aotearoa New Zealand is a small country, individual New Zealanders have big carbon footprints. The average New Zealander emits over 16 tonnes of greenhouse gases every year - more than the average European, and over twice the average Chinese person's emissions.

We are one of the 30 biggest per capita emitters in the world, and our emissions are still growing. Our emissions are projected to have grown by 32-37% from 1990 to 2020.

© James Frankham / WWF

The argument is over. Anyone that doesn't believe that climate change is happening doesn't believe in science.

Leonardo DiCaprio

We don't know where the tipping points are

The thing is, temperature rise won't be linear. Part of what makes climate change so urgent is that temperatures will continue to increase long after greenhouse gas emissions are curbed.

Scientists believe the planet may reach one or more ‘tipping points’, where changes will become irreversible or positive feedback loops will be triggered. One example is the melting of ice sheets, which will drastically effect both sea levels and the planet's entire climate system.

© / Bryan and Cherry Alexander / WWF


Climate scientists agree that humanity is responsible for the vast majority of global warming

The Intergovernmental Panel on Climate Change, the United Nations Environment Program’s climate body, has said for over a decade that there is “unequivocal” evidence that the planet is warming and that the temperature increase is “very likely” due to human-made greenhouse gas emissions.

The IPCC does not carry out research itself but bases its assessment on peer reviewed and published scientific/technical literature.

The Panel is made up of 2500+ scientific expert reviewers, 800+ contributing authors, and 450+ lead authors from 130+ countries.

Over 97% of peer reviewed journal articles on climate science agree with the scientific consensus around climate change.

But we have the solutions

The good news is: we have the solutions. Real, technically feasible, affordable alternatives to fossil fuels exist now.

To keep warming below 1.5˚C, we need to make the switch from fossil fuels to 100% renewable energy and bring our carbon pollution down to net zero by 2050.

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© Adam Oswell/WWF

Climate change is the biggest issue facing the planet. People, species, and our precious environment are all at risk.

Our carbon pollution will have impacts all over the world - including here in Aotearoa New Zealand. Climate change is bigger than politics. This affects everyone.

But we know the solutions. Together, a 100% renewable energy future is 100% possible. The transition is already underway.


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Climate change is already affecting New Zealand. Our people and ecosystems are already feeling the heat.

Already, the national average temperature has risen by 0.9˚C since 1900. South Island glaciers are retreating, and we're recording fewer frosts. New Zealand ports have measured an average 16cm of sea level rise over the last 100 years. And businesses and people are already paying more for insurance to deal with extreme weather, like floods and droughts.

We can expect a lot more to come. Climate change will almost certainly cause more droughts, particularly in Northland and the East Cape. It will mean increased rainfall in other areas, particularly the West Coast, and an increased risk of flooding. Coastal areas will face greater erosion, and possible inundation. 

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People around the world are already feeling the impacts of climate change. Water supplies are shrinking, crop yields are dropping, forests are burning, and our oceans are becoming more acidic. This has huge implications for our livelihoods and human security.

Fragile ecosystems, like coral reefs, are also already succumbing to climate change impacts. Melting glaciers, rising sea levels, and new and more frequent weather extremes will leave no continent untouched. 

If we let the warming continue unchecked, we run a real risk of hitting catastrophic tipping points. That's where the warming triggers positive feedback loops that lead to even more warming.

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To avoid the worst impacts of climate change, scientists warn that average global temperatures should not be allowed to rise more than 1.5˚C above pre-industrial levels. 

When the world's governments committed to the Paris Agreement in 2015 - a new, global deal on climate change - they answered a call from our Pasifika neighbours, and agreed to try to keep warming below 1.5˚C.

A rise in temperature above 1.5˚C could lead to a significant rise in sea levels, potentially displacing tens of millions of people, especially in the Pacific), a dramatic reduction in global food supplies, water shortages affecting hundreds of millions of people, and an increased risk of extinction for up to 30% of the world’s species.

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The good news is: we have the solutions. Real, technically feasible, affordable alternatives to fossil fuels exist now. To keep warming below 1.5˚C, we need to make the switch from fossil fuels to 100% renewable energy and bring our carbon pollution down to net zero by 2050.

Thing is, this won't just stop climate change. Switching from dirty fossil fuels to clean renewable energy will be better for people, communities and businesses all over the world.

And the change is already underway. Renewable energy technologies like wind and solar are getting cheaper and cheaper, and rolling out worldwide faster and faster. We can do this.

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