The average ground-level air temperature stayed relatively constant in the thousand years leading up to the Industrial Revolution. Since the end of the 19th century, however, we have observed a rise in the global temperature. From the time temperature records first began in 1880, up to 2016, the average global ground-level air temperature increased by more than 1C.
Climate change is increasingly causing record-breaking high temperature and heatwaves.
Most of the sun’s rays penetrate the Earth’s atmosphere and reach its surface. These rays are absorbed by the Earth and are then released as thermal radiation, or heat. Without the presence of certain gases in the atmosphere, such as water vapour (H2O), carbon dioxide (CO2), ozone (O3), nitrous oxide (N2O) and methane (CH4), this thermal radiation would simply escape back into space. Instead, thanks to this layer of naturally occurring gases, thermal radiation is absorbed and then released again, in all directions – including back down towards the surface of the Earth. This process of warming is known as the “natural greenhouse effect”.
Since the start of industrialisation, there has been a sharp increase not only in the average global air temperature but in the concentration of carbon dioxide and other greenhouses in the atmosphere. Human activity, in particular the burning of fossil fuels, is the reason for this change. Gases released by human activity are called anthropogenic or “man-made” gases, because just like natural greenhouse gases, they prevent the escape of thermal radiation from the Earth back into space.
The burning of fossil fuels (coal, petroleum and natural gas) to generate energy accounted for approximately 85 per cent of global CO2 emissions in 2014. Another source of CO2 emissions is the large-scale felling of trees in Europe and North America several hundred years ago. Today, it is mainly tropical rainforest that is being cut down and cleared to build roads, develop pastureland, produce timber or to plant crops for export such as oil palms, bananas, soy and coffee.
Oceans cover more than 70% of the Earth’s surface. They are of enormous importance for maintaining our climate, as they transport vast quantities of heat around the world. They also act as a buffer against global warming, because they absorb some man-made CO2 emissions as well as a large part of the energy that is retained on Earth as a result of the man-made greenhouse effect.
Because higher temperatures allow the air to hold more water vapour, the water vapour content in the Earth’s atmosphere is increasing. Higher temperatures also allow more water to evaporate, and thus higher precipitation levels may be expected. At present, about 18 % of the world’s heavy rainfalls on land can be attributed to global warming.
Tropical cyclones form over the ocean when the water temperature rises above 26C, as they are powered by warm, humid air. Climate change is causing the temperature of the sea surface to rise and consequently evaporation is increasing in turn, thus feeding more energy to the storms and increasing the chance of more severe storms occurring.
Climate change is already directly or indirectly affecting the lives of all 7.8 billion people on Earth. The consequences of climate change affect human health in a variety of ways. Heat stress can exacerbate heart conditions and circulatory and respiratory diseases. High temperatures also boost the formation of ground-level ozone, which can compromise lung function. Increasingly frequent extreme weather events such as floods or storms pose numerous risks to people. Heavy rainfall and flooding can cause microbial contamination of rivers and coastal waters, leading to an increased risk of outbreaks of waterborne infectious diseases.
Climate change is not some far-off reality. The decisions we make as manufacturers and consumers affect the outcomes for generations to come. Led by sustainability becoming more and more important in how business is done today, incremental and significant steps are needed to reduce carbon emissions that threaten our planet today.
Adapted from Small Gases, Big Effect by David Nelles and Christian Serrer, which is published by Allen Lane
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