Let's talk more specifically. There are three massive systems that operate on a global scale. These three systems are extremely important for regulating the overall condition of the Earth and have known tipping points. They are:
- Climate System
- Ozone Layer
- Oceans
1. Climate System
The climate system connects the oceans, land, ice sheets, atmosphere, and rich biodiversity. It has been observed that the Earth's average temperature has fluctuated by only about 1°C over the past 10,000 years.
However, the current average temperature has risen by 1.1°C, and it is predicted that the Earth will surpass several tipping points between a 1°C and 2°C increase in temperature. The effects are already becoming visible, including record high temperatures over the past 20 years, remarkable ice melt, coral reef die-offs, and reduced carbon sequestration in the Amazon. Based on scientific research, world leaders met in Paris in 2015 and agreed to aim to keep global warming below 2°C, and preferably below 1.5°C.
2. Ozone Layer
The ozone layer, Earth’s protective shield, absorbs harmful ultraviolet (UV) rays from the Sun, safeguarding life on Earth. Without the ozone layer, radiation would damage plants, animals, and human DNA, leading to skin cancer.
In the 1980s, new chemicals were invented by humans that drifted into the upper atmosphere and nearly caused a crisis in ozone layer destruction. However, in 1987, the Montreal Protocol on Substances that Deplete the Ozone Layer was adopted, and the situation has stabilized since then. The ozone layer is measured in Dobson Units (DU), with a threshold set at 275 DU.
3. Ocean
Oceans cover 70% of the Earth's surface. They are so vast and seemingly infinite that it's easy to assume that throwing garbage into them won't have much impact, but that is not the case.
The oceans are indeed suffering significant damage. They regulate heat exchange between the atmosphere and the sea surface, support rich biodiversity, and control nutrient flow and water circulation. Functional and stable oceans are a prerequisite for a functional and stable Earth. The oceans absorb 93% of the heat generated by burning fossil fuels. It is essential to stop ocean acidification.
Due to carbon dioxide emissions from fossil fuel combustion, ocean acidity has increased by a disheartening 26% since the start of the Industrial Revolution. Current rates of ocean acidification are occurring much faster than during the Paleocene epoch 55 million years ago, which experienced a slower rise. If this situation persists, the results will undoubtedly be catastrophic. Organisms like calcifying phytoplankton, corals, and oysters, which rely on calcium carbonate to build their shells and skeletons, will struggle to grow.
Oyster farmers are already experiencing these effects, and corals are dying due to heatwaves, increased ocean acidification, and pollution. At present, the Earth remains within the limits of ocean acidification, but realistically, the only way to stop it is to reduce emissions from fossil fuels. Closely related to these three systems are the four boundaries of the biosphere (biodiversity, land, freshwater, and nutrients). While there is no strong chemical evidence to suggest that crossing these boundaries would lead to global tipping points, the boundaries of the biosphere are extremely important. Although not discussed here in detail, if you're interested, please look into it further.
Owen Gaffney and Johan Rockström. The Limits of the Earth: How to Solve Global Warming and Earth’s Crises. Translated by Saki Toda. Kōdansha, 2022, 379 pages.
