Polar Bear (Ursus arctos maritimus) mother and two cubs playing around iceberg.

What are climate change and global warming?

What is climate change?

The science is clear. Climate change is real. Climate change is happening now. Climate change requires immediate and ambitious action to prevent the worst effects it can have on people and wildlife all over the world.

We know that the planet has warmed by an average of nearly 1°C in the past century. If we are to prevent the worst effects of climate change, there is global agreement that temperature rises need to be kept well below 2°C from the pre-industrial era, with an ambition to keep it below 1.5°C. Currently, however, assessments suggest that we are currently on course for temperature rises of up to as much as 4°C or higher.

We have recently seen a number of unwanted developments:

16 of the 17 warmest years on record have occurred since 2001, with 2016 being the warmest yet.
The current levels of atmospheric concentrations of greenhouse gases are unprecedented in the last 800,000 years.
And recently, scientists have declared a new geological time period: the Anthropocene, in which human activity is said to be the dominant influence on the environment, climate, and ecology the earth.

As the planet continues to warm, climate patterns change. Extreme and unpredictable weather will become more common across the world as climate patterns change, with some places being hotter, some places being wetter, and some places being drier. These changes can have (and are already having) drastic impacts on all life on Earth.

What causes climate change?

Burning fossil fuels

Over the past 150 years, the world’s industrialised nations have changed the balance of the carbon cycle by burning huge amounts of fossil fuels (concentrated carbon such as coal, oil and gas)

Breeding cattle and cutting down forests

Industrialised nations have also breeding vast numbers of methane-producing livestock and cutting down the forests that naturally absorb carbon dioxide from the air.

Trapped carbon dioxide

The extra carbon dioxide in the atmosphere traps more of the sun’s heat, so it’s been raising global temperatures. The speed of change has been faster than any natural process, and faster than many natural systems can adapt.

How hot can it get?

A rise of just 2°c would mean:

Severe storms and floods in many countries, particularly impacting coastal areas, with droughts also affecting many parts of the world
Seas become more acidic, coral and krill die, food chains are destroyed
Little or no Arctic sea ice in summer – which not only means less habitat for polar bears, but also means the global climate warms faster, as there is less polar ice to reflect sunlight

Beyond 2°c:

Rainforests dying
Unthinkable loss of ancient ice sheets of Greenland and Antarctica, causing dramatic sea level rises
Mass displacement of people and widespread species loss and extinction

That’s why we must act now.

Some people might try to tell you that global warming is natural, or that the Earth is actually cooling. Or they might suggest there’s nothing we can do. But here’s what the science tells us:

Temperatures are rising faster than ever:

Yes, the Earth’s climate has always changed, with temperatures rising and falling over thousands of years. But now, it’s happening now at a far faster rate than ever before, giving people and wildlife very little time to react and adapt.

Global warming is man-made:

There is overwhelming evidence (97% scientific consensus) that global warming is mostly man-made – largely down to burning fossil fuels and deforestation on a mass-scale. This is not a natural process, no matter how much climate change deniers may claim it is.

The good news? We can do something about it. But we have to do it together, and we have to do it now.

Global warming terms explained:

Climate change

A change in global or regional climate patterns caused by the increasing levels of greenhouse gases in the atmosphere since the Industrial Revolution, as a result of the use of fossil fuels.

Global warming

An increase in global average temperatures of the Earth's atmosphere through the greenhouse effect, which is caused by increases of pollutants, such as carbon dioxide and methane.

Carbon dioxide (CO2)

Carbon dioxide is a natural gas. It’s essential for all life on Earth. It’s absorbed by plants as they grow, and emitted by all life forms when they respire and when they die (or when they’re burned as fuel). Other than water vapour, it’s the most common greenhouse gas.

Greenhouse gases

Greenhouse gases include carbon-based gases such as carbon dioxide and methane. They’re vital in the Earth’s atmosphere in certain quantities because they help trap and retain some of the sun’s heat (the ‘greenhouse effect’). This makes life as we know it possible on Earth – without it the world would be mostly frozen. But too much is dangerous, too.

Carbon cycle

The carbon cycle is the natural process by which carbon gases are emitted and absorbed across the globe. This determines the overall levels of carbon gases in the atmosphere.

Tipping points and feedback effects

As the Earth warms, the impacts can fuel each other and cause runaway, irreversible changes. For instance, polar ice reflects sunlight away from the Earth. But when it melts, more heat will be absorbed instead. Also, thawing permafrost releases trapped methane, and drying forests and warming oceans emit their stores of carbon dioxide – all further increasing the greenhouse effect.

Polar Bear (Ursus maritimus) cub curled up on mother, Wapusk National Park, Manitoba, Canada

How you can help tackle climate change