Climate Change Unveiled: 24 Crucial Facts You Can’t Ignore

Climate Change Unveiled: 24 Crucial Facts You Can’t Ignore

Delve into the essential facts about climate change that everyone should know, as highlighted by David Nelles and Christian Serrer, authors of Small Gases, Big Effect.

The Global Temperature Surge

For a millennium leading up to the Industrial Revolution, the northern hemisphere’s average ground-level air temperature remained relatively stable. However, since the late 19th century, we’ve witnessed a significant rise in global temperatures. From 1880 to 2016, the average global ground-level air temperature increased by over 1°C.

The Natural Greenhouse Effect Explained

Most of the sun’s rays penetrate the Earth’s atmosphere and reach its surface. These rays are absorbed and then released as thermal radiation or heat. Without certain gases like water vapor, carbon dioxide, ozone, nitrous oxide, and methane, this thermal radiation would escape into space, making the climate about 33°C colder and freezing the entire planet. Thanks to these naturally occurring gases, thermal radiation is absorbed and released in all directions, including back towards the Earth’s surface, creating the “natural greenhouse effect.”

The Rise of Man-Made Greenhouse Gases

Since industrialization, there has been a sharp increase in both the average global air temperature and the concentration of carbon dioxide and other greenhouse gases in the atmosphere. Human activities, particularly the burning of fossil fuels, are responsible for this change. These man-made gases prevent thermal radiation from escaping back into space, causing the Earth’s surface to absorb more heat than it otherwise would.

Human Impact on the Carbon Cycle

In 2015, China was the largest emitter of carbon dioxide from burning fossil fuels. Oceans, soils, and vegetation release and absorb carbon dioxide. Over the past decade, humans have released 39 gigatonnes of CO2 annually. About 28% is captured by vegetation and soils, 22% is absorbed by the oceans, and the remaining 44% stays in the atmosphere. This sudden release of CO2 has disrupted the natural carbon cycle, leading to more acidic oceans and higher CO2 concentrations than ever before in the past 800,000 years.

Sources of Carbon Dioxide Emissions

The burning of fossil fuels (coal, petroleum, and natural gas) for energy accounted for approximately 85% of global CO2 emissions in 2014. Cement production was responsible for 5%, and changes in land use for 10%. Deforestation in Europe and North America several hundred years ago also contributed to CO2 emissions. Today, tropical rainforests are being cleared for roads, pasture land, timber, and crops like oil palms, bananas, soy, and coffee. From 2000 to 2009, forested areas were lost at an average rate of 35 football fields per minute.

Historical Emissions and Their Impact

While China was the biggest emitter in 2015, historical emissions tell a different story. Between 1918 and 2012, the EU and US emitted much more CO2 than China. Emissions from manufacturing are allocated to the country of production, but if calculated by consumption, China, India, and Russia’s per capita emissions would decrease, while those of European countries and the US would increase.

Sources of Methane Emissions

From 2000 to 2009, 29% of global man-made methane emissions came from fossil fuel extraction. Livestock farming generated nearly as much methane, and decomposing waste in landfill sites released almost another quarter. Flooded rice fields, burning biomass, and biofuel manufacturing also contribute to methane emissions.

Sources of Nitrous Oxide Emissions

Agriculture is the largest contributor to nitrous oxide emissions, accounting for 59%. Fertilizers contain nitrogen compounds that are broken down by bacteria in the soil, releasing nitrous oxide. Livestock excretions and rivers also release nitrous oxide, as nitrogen compounds are washed into waterways through sewage and farming fertilisers.

The Melting Arctic Sea Ice

The consequences of climate change are particularly evident in the Arctic, where air temperatures are increasing faster than the global average. From 1979 to 2016, the minimum area covered by sea ice in the Arctic fell by approximately 43%, and the ice cover’s thickness shrank by around 77%. Snow and ice reflect solar radiation back into space. When they melt, the darker area beneath absorbs more heat, causing further warming and more melting. This cycle results in the ocean absorbing more heat, melting the ice not only due to solar radiation but also because of warmer seawater.

Retreating Glaciers

Almost all glaciers worldwide are gradually losing mass. There is also less snow coverage in the northern hemisphere. Since 1966, the surface area of land covered with snow has decreased at an average rate, further evidence of the impact of climate change.

For more information, visit the NASA website.