Climate change is having extreme and visible effects around the world. Temperatures are rising to record highs in some regions, causing wildfires and affecting crop yields, whereas other areas are experiencing heavy rainfalls and devastating floods. There is broad consensus that the steep increase in greenhouse gas emissions is chiefly responsible for the continuous rise of the Earth’s temperature and the effects we are witnessing as a result (see here, here, and here).
The fact that global warming is caused by a process called the greenhouse effect has become a standard feature in school curricula and is familiar to many of us. However, it is still worth to recap what the causes, as well as the present and future consequences of climate change are in order to understand what we can do to tackle this challenge on a global level.
What is climate change?
Simply put, climate change refers to long-term shifts in temperatures and weather patterns. There have always been changes in the Earth's climate over its billions of years long history, which have been shown through phases such as the ice age. These would be considered to be natural causes of climate change. However, these changes happened over thousands of years, rather than the short space of time we have seen since the Industrial Revolution.
The main way humans are causing this accelerated climate change process is through greenhouse gas emissions. Greenhouse gases do occur naturally but human activities, such as the burning of fossil fuels, deforestation, as well as agriculture and land use changes, have increased their concentration significantly.
Human activities, such as burning fossil fuels, have drastically increased the CO₂ level in the atmosphere, causing global warming.
The types of greenhouse gases that are a cause of climate change are:
- Carbon dioxide (CO2)
- Methane (CH4)
- Nitrous oxide (N2O)
- Fluorinated gases
However, carbon dioxide emissions are by far the biggest contributor to climate change. In fact, by 2020, the level of carbon dioxide in the air had risen to 48% above its pre-Industrial Revolution level.
Once greenhouse gases are emitted, they absorb and re-emit infrared energy, trapping heat in the Earth’s atmosphere, which is known as the greenhouse effect. Just as greenhouse gases exist naturally, so does the greenhouse effect. It is the reason why the Earth has a temperature that made it possible for life to develop, but as the amount of greenhouse gas emissions has increased so heavily, this natural process has been disturbed.
Since the start of the Industrial Revolution in the late 1800s, human activities have caused the Earth’s temperature to increase by 1 degree, and we are on track to exceed a warming level by 1.5 degrees within the next decade. This does not sound like much but puts a heavy burden on our global climate system.
Climate change does not just mean it is getting warmer – and it is not affecting everyone equally
Even though scientists warn that we must not exceed a global temperature increase of more than 1.5 degrees, it is important to note that there will not be a single 1.5-degree warmer world. For example, Switzerland has already seen a 2 degree increase in temperature since 1864.
Swiss glaciers are increasingly retreating.
Furthermore, women, children, people of colour and indigenous communities, particularly those in developing countries, are going to experience the biggest impacts. International cooperation is therefore needed, especially since developed countries are responsible for 79% of global greenhouse gas emissions.
Four of the major changes that we can expect to see, or are already seeing, as the Earth’s climate continues to change are outlined below:
- More droughts and heatwaves - Climate change will increase the frequency and intensity of droughts and heatwaves across the world, which will result in optimal conditions for wildfires to take place. Apart from posing risks to people and wildlife, wildfires also disrupt transportation, communications and energy supplies.
Developing nations are especially vulnerable to the further effects of drought. Between 2005 and 2015, more than 80% of drought-induced economic loss in developing nations related to livestock, crops and fisheries. This leads to both food shortages and loss of income, and can even go on to exacerbate existing issues like civil war. However, this impact of climate change is not only confined to developing countries. In 2021, the US experienced an estimated $17 billion in crop losses during a record dry spell in 2012. - Increased levels of precipitation causing flooding - Another consequence of global warming is that a warmer planet will lead to increased rainfall. This is because warmer air can hold more moisture, with this equating to about 7% more moisture for every degree of temperature change. As a result, existing heavy rainfall patterns intensify, leading to more flooding and resulting damage.
- Hurricanes will become more dangerous - As long as the climate continues to warm, hurricanes are set to become more intense. Since 1975 there has been a substantial increase in the amount of category 4 and 5 hurricanes, equating to a 25-30% rise for every 1°C of human-induced global warming.
Hurricanes are already some of the costliest natural disasters. The trio of Harvey, Maria and Irma that hit the US in 2017 accounted for $268 billion worth of damage alone. - Sea levels will continue to rise - Global mean sea levels have risen between 21-24cm since 1880, a third of which has happened in the last 25 years. By 2100, sea levels are predicted to rise by up to 84cm further. This will cause destructive coastal erosion, soil contamination, wetland flooding and habitat loss.
We need large-scale mitigation measures to stop climate change
Although there are damages that cannot be undone, there is time to act. This will require large-scale changes to how the world operates, for example a shift towards renewable energy.
Switching from fossil fuels to renewable energy is crucial to reduce CO₂ emissions.
Energy is one of the most important areas for climate change mitigation because it accounts for over 60% of global greenhouse gas emissions, and fossil fuels still make up more than 80% of the energy mix. In order to limit global warming to 1.5 degrees as set out by the Paris Agreement, we must reduce our annual CO₂ emissions to 25 billion tons by 2030 instead of the 56 billion tons we will likely reach by that time.
It is estimated that governments spend around $600 billion annually on subsidizing fossil fuels, a number five times higher than the amount spent on supporting clean energy. Investing less in fossil fuels and more in clean energy could therefore help to reduce the concentration of CO₂ in the atmosphere. In terms of CO₂ emissions, coal is the most polluting fuel, yet it is the least taxed: 85% of coal used for heating and industrial processes is untaxed and the average tax rate on coal is below €2 per ton of CO₂. Putting a price on carbon and taxing the use of fossil fuels could also provide an incentive to move towards clean energy.
However, phasing out the use of fossil fuels and moving towards a low carbon economy is only possible if renewable energy sources are readily available. The major types of renewable energy sources are energy from biomass, hydropower, geothermal energy, wind energy, and solar energy.
What about the tons of CO₂ we have already emitted?
Large-scale mitigation measures like reducing greenhouse gases by shifting to renewable energy are crucial. Nevertheless, they will take more time to come into effect than we would ideally like them to. We at Climeworks believe that it is important to empower everyone to make an impact - now. Climeworks has developed a direct air capture technology, which permanently removes carbon dioxide from the atmosphere. This is crucial to address historic as well as unavoidable emissions and thus enable the world to truly get to net-zero emissions by mid-century.
Climeworks' direct air capture and storage plant Orca in Iceland.
Everyone can join Climeworks’ mission: when becoming a Climeworks Pioneer, we remove CO₂ from the air in your name. Since we can measure how much CO₂ is removed with our direct air capture machines, we can tell you exactly how much carbon dioxide removal you have enabled. As a Pioneer, you will join over 9’000 individuals as well as leading businesses like Microsoft, Shopify and Swiss Re that already act and remove CO₂ from the air.