Climate change: causes and consequences

The climate crisis, together with the loss of biodiversity, is the greatest challenge facing our world. Right now, increased global average temperatures are having a profound effect on our climate and those effects will become more severe in the coming years.

Now is our chance to act and prevent further climate change. If we are to keep global temperature rise to below 1.5 degrees Celsius compared to preindustrial levels, man-made greenhouse gas emissions need to drop by at least 50% by 2030 according to the IPCC. On this page, we summarise what the climate crisis is, what is causing it, and what you can do to help prevent it.

What is climate change?

The climate is naturally variable. This variability is normal and is due to many factors that interact with each other, such as changes in ocean currents, volcanic activity, solar radiation, major climate events like El Niño, and the strength of the Indian Monsoon, etc.

Climate change, then, is a significant and lasting change in the statistical distribution of weather patterns. This can happen over a period ranging from decades to millions of years. This could be changes in the average weather conditions, such as the average date the wet season begins in the tropics, or it could be changes in the frequency of extreme weather events like floods, droughts, and storms.

Changes in the orbital patterns of the Earth, called the Milankovitch cycles, are the most significant driver of climate change over a period of thousands to millions of years. They have been the main driving force behind the last four cycles of ice ages and warmer periods in between. However, the earth’s climate has changed significantly over the last 150 years and it is extremely important that we understand what is causing the change over such a short period of time.

Over the past century, the climate has been warming on a global scale

Many studies have conclusively demonstrated that global average temperatures have been increasing since the mid-1900s. This is popularly called global warming and the scientific consensus is that it is being caused by human activities, primarily through the emission of CO2 into the atmosphere through the burning of fossil fuels. Anthropogenic climate change, as it is often called, has been demonstrated to be the consensus among climate scientists.

The landmark IPCC special report on global warming of 1.5 ºC, published in October 2018, demonstrated that human activities have already had a major impact on global temperatures and that temperatures are continuing to rise: “Human activities are estimated to have caused approximately 1.0 °C of global warming above pre-industrial levels, with a likely range of 0.8 °C to 1.2 °C. Global warming is likely to reach 1.5 °C between 2030 and 2052 if it continues to increase at the current rate (high confidence).”. These findings have later been reconfirmed many times, for example in the IPCC’s 6th Assessment Report, published between 2021 and 2023.

Though a temperature rise of 1.5 degrees Celsius does not sound like a lot, the IPCC report shows that this will have grave consequences. You can see the changes in temperature over the past century through images from NASA, as seen below:

What causes global warming?

Temperatures on Earth are liveable because of a natural process called the greenhouse effect. When the sun’s radiation reaches our atmosphere, some is reflected back into space, while some passes through and is absorbed by the Earth. This causes the surface of the Earth to warm up. The heat from the Earth is radiated outward and absorbed by gases present in the Earth’s atmosphere. These are called “greenhouse gases”. These gases prevent heat from disappearing back into space and keep the Earth at an average temperature of about +15 °C instead of -18 °C.

Picture: Human-induced greenhouse effect, source: US National Park Service

Over the past century, humans have been putting more greenhouse gases into the atmosphere, increasing the greenhouse effect. Many of these gases come from burning fossil fuels in factories, cars, and planes or from agriculture. Carbon Dioxide is the gas most responsible for warming, mostly because it is so abundant. Other greenhouse gases include methane, nitrous oxide, CFCs, HCFCs, and Methyl Bromide.

The loss of forests and wetlands, that otherwise would store CO2, also exacerbates the warming effect. An estimated 80,000 acres of tropical rainforest are cut down every day, mostly for either the logging industry or to clear space for agriculture.


Climate change is altering our environment, economy, health, and communities in diverse ways. Scientists warn that if we do not make substantial changes in order to keep global temperature rises below 1.5 °C, the results will be disastrous.

The IPCC special report on global warming of 1.5 °C was commissioned with the intention of establishing a scientific understanding of what the consequences are of a 1.5 °C global warming scenario, and of higher temperature scenarios. Here we summarise some of them:

  • Sea level rise due to water expanding at warmer temperatures and the melting of glaciers.
  • Increased intensity and frequency of weather extremes like hurricanes, floods, droughts, and storms.
  • Increased water scarcity in some areas leading to desertification and decreased crop yields. This could also feed into existing regional tensions, exacerbating the likelihood of conflict.
  • Less reliable and predictable seasons, making long-term planning more difficult and crop failures and food shortages more likely.
  • Ocean acidification decreasing yields in the fishing industry and destroying coral reefs.
  • Habitat loss due to the climate changing faster than species can adapt. This will lead to the loss of important species, biodiversity, and important ecosystems.
  • Changes to the geographical range of species.
  • Increased disease, particularly Malaria and Dengue fever, as mosquitoes are able to survive at higher latitudes and altitudes.

It used to be thought that fighting climate change would require a massive financial cost, which may explain why many countries and people were reluctant to do anything. That is no longer considered the case as the economic impact of climate change will be enormous. Climate change is a lose-lose situation for everyone. It is in all our interests to prevent it!

The urgency of action

The IPCC special report on global warming of 1.5 °C tells us that, as of 2018, we have only 12 years left in which to limit global warming to a maximum of 1.5 °C (see paragraph C.1 in the summary for policymakers). What that means in practise is that greenhouse gas emissions need to be cut steeply starting from now!

Fortunately, there is a lot that you can do about this. The root cause of climate change is that many of us live highly unsustainable lifestyles with large carbon footprints. It is all about changing our lifestyles to be more sustainable and encouraging others to do the same.

An easy first step is to buy green energy. Today, 31% of global greenhouse gas emissions are created during the production of heat and electricity, while many other sectors are indirectly related to energy production. So, using clean energy in your home and business makes a big difference. EKOenergy is a nonprofit ecolabel that promotes energy that is produced according to strict sustainability criteria. You can help support a global transition to renewable energy by buying an energy tariff that supports the EKOenergy ecolabel. It does not matter where you are in the world, ask your energy seller if they can offer you EKOenergy or see the list of sellers that already support the ecolabel.

What can you do to help fight climate change?

The two single biggest things that any individual can do to reduce their carbon footprint is to reduce their meat consumption and try to avoid flying as much as possible.

On top of this, here are a number of other suggestions:

  • Encourage your local politicians to support pro-environmental policies and show that you care about climate change.
  • Increase your energy efficiency as much as possible.
  • Buy renewable electricity and green gas, such as products that carry the EKOenergy ecolabel.
  • Think about how the food you eat is produced. Try the vegan and vegetarian options and buy ecolabelled products.
  • Favour holiday destinations that are closer to home, in which you don’t need to take a flight.
  • Avoid single-use materials and reuse as much as possible instead.
  • If you can’t reuse, then recycle your waste.
  • Take public transport, carpool, or cycle where possible.
  • Think about how your clothes are made and buy sustainable fashion brands.
  • Join a local activist group like #FridaysForFuture or Extinction Rebellion. If there is not one near where you live, then start your own.
  • Carbon offset the carbon emissions that you can’t avoid.

Above all, get active and start talking about climate change and how we can live sustainably.

There are loads of innovative ideas out there for how you can reduce your carbon footprint, check out some of these links:

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