The Consequences of the BAU Trajectory

In this chapter, Emmanuel Guérin discusses the consequences of temperature increases that result from rising greenhouse gas emissions. Global warming of 4 degrees Celsius or more would have serve and irreversible impacts that would threaten our ability to adapt and our economic future. Three of the most important risks of climate change going forwards are sea level rise, ocean acidification, and the increased frequency and intensity of extreme weather events. Sea level rise is caused nu thermal expansion of the ocean as well as the addition of water to the oceans due to the melting and discharge of ice from mountain glaciers and from ice sheets. A global warming of 4 degrees Celsius would lead to a sea level rise of 0.5-1 meter by the end of the century, but would continue long after that to about 4-6 meters by 2300. Any rise in sea level has disastrous consequences for coastal settlements. Oceans are one of the Earth’s largest sinks for atmospheric CO2. As this CO2 gas reacts with the water, it forms a weak acid that leads to ocean acidification and will cause the large-scale extinction of marine species like coral reefs and on the functioning of the ecosystem as a whole. A global warming of 4 degrees Celsius would not be every distributed across the world, but some part of the world would experience higher increases in temperature, meaning that only some places would experience the extreme heat waves that could become a new normal. these heat waves have effects like harvest losses, forest fires, and drought, etc. Global warming would also increase the frequency of heavy precipitation in certain parts of the globe and could induce the breakdown of infrastructure networks and critical services. Global climate change jeopardizes countries’ abilities to achieve even the most basic social and economic goals in the future, including the eradication of poverty. This video is part of the module The 2-Degree Limit.

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