What is climate change? A really simple guide

Parched Earth

World temperatures are rising due to human activity and climate change is now threatening every aspect of human life.

Without containment, humans and nature will experience catastrophic warming, with worsening droughts, rising sea levels and mass extinctions of species.

The world faces a major challenge, but there are potential solutions.

What is climate change?

Climate is the average weather in a place over many years. Climate change is a shift in these average conditions.

The rapid climate change we are now witnessing is being caused by people using oil, gas and coal for their homes, factories and transportation.

When these fossil fuels burn, they emit greenhouse gases – mainly carbon dioxide (CO2). These gases trap heat from the sun and raise the planet’s temperature.

The world is now about 1.1°C warmer than it was in the 19th century – and the amount of CO2 in the atmosphere has increased by 50%.

Bar chart showing how the world warmed between 1850 and 2020

Bar chart showing how the world warmed between 1850 and 2020

According to climate scientists, the rise in temperature must be slowed down if we are to avoid the worst effects of climate change. They say global warming must be kept to 1.5 degrees by 2100.

However, if no further action is taken, the planet could still warm by more than 2°C by then. A 2021 report by the independent Climate Action Tracker Group calculated that the world was heading for 2.4°C of warming by the end of the century.

If nothing is done, scientists believe global warming could exceed 4°C in the future, leading to devastating heat waves, millions losing their homes to rising sea levels, and irreversible loss of plant and animal species.

What are the effects of climate change?

Extreme weather events are already increasing in intensity around the world, threatening lives and livelihoods.

With further warming, some regions could become uninhabitable as farmland turns to desert. East Africa has just experienced its fifth rainy season, which has threatened up to 22 million people with severe hunger, according to the United Nations World Food Programme.

Extreme temperatures can also increase the risk of wildfires – as seen in Europe last summer. Between January and mid-July 2022, France and Germany recorded around seven times more area burned than average.

Hotter temperatures also mean previously frozen ground in places like Siberia is melting, releasing greenhouse gases that have been trapped in the atmosphere for centuries, further exacerbating climate change.

Elsewhere, extreme rains last year caused historic flooding — like in China, Pakistan and Nigeria.

People living in developing countries are likely to suffer the most as they have fewer resources to adapt to climate change. But these nations are frustrated because they have produced the fewest greenhouse gas emissions.



The planet’s oceans and habitats are also under threat. A study published in April 2022 and funded by the US National Oceanic and Atmospheric Administration suggests that between 10% and 15% of marine species are already threatened with extinction.

In a warmer world, land animals will also have a harder time finding the food and water they need to survive. For example, polar bears could become extinct if the ice they depend on melts, and elephants will struggle to find the 150 to 300 liters of water they need each day.

Scientists believe at least 550 species could be lost this century unless action is taken.

Coral reef

If temperatures continue to rise, almost all warm-water coral reefs could be destroyed

How will climate change affect the world?

Climate change will have different impacts around the world. According to the UN climate panel IPCC, if global temperature rise cannot be kept within 1.5°C:

  • The United Kingdom And Europe becomes prone to flooding from extreme rainfall

  • countries in middle East will experience extreme heat waves and widespread droughts

  • island states in Pacific region could disappear under the rising sea

  • Many African nations are expected to suffer from drought and food shortages

  • Drought conditions are likely in the west USwhile other areas will see more intense storms

  • Australia is likely to experience extreme heat and an increase in wildfire deaths

Somali IDP Habiba Bile and her children stand near the carcasses of their dead cattle after severe drought near Dollow, Somalia

Habiba Bile and her children stand next to the carcasses of their dead cattle after severe droughts near Dollow, Somalia, in 2022

What do governments do?

Countries agree that climate change can only be tackled together, and in a landmark agreement in Paris in 2015 they pledged to try to limit global warming to 1.5C.

In November 2022, Egypt hosted a summit of leaders, dubbed COP27, which brought countries together to make new commitments to tackle climate change.

Many countries have committed to “net zero” by 2050. That means reducing greenhouse gas emissions as much as possible and offsetting the remaining emissions by absorbing an equal amount from the atmosphere.

Experts agree it can still be done, but governments, businesses and individuals need to make significant changes now.

What can individuals do?

Big changes must come from governments and corporations, but scientists say some small changes in our lives can limit our impact on climate:

More on the subject of climate change below

More on the subject of climate change below

Top image from Getty Images. Visualization of climate strips courtesy of Prof Ed Hawkins and University of Reading.

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