What Happens if the World Warms Up by 2°C?

The 2015 United Nations Climate Change Conference saw 147 countries agree to drastically reduce their greenhouse gas emissions in order to keep global warming below 2°C, compared to pre-industrial levels. This pledge is the first move towards the development of plans and policies that seek to tilt the global economy towards cleaner, more sustainable ways of living and doing business. However, as climate experts point out, this effort might not be enough. In a previous article, it was mentioned that most countries that attended COP21, including major polluters like the United States, lack the capacity to start reducing their emissions immediately, as they do not have a set strategy for the near or long term regarding this matter.

A 2°C warming over pre-industrial levels would threaten food security for the world's population - Photo Credit: Wikipedia

The issue is made more alarming when taking into account that the proposals submitted by attending countries were deemed insufficient by scientists. An article on the topic published on The Guardian’s website, says that global emissions are currently rounding 50 billion tons a year and they are set to keep increasing, even if all the proposed measures are implemented. The increment is estimated to reach 55 to 60 billion tons by 2030. This significantly diverges from the 14 billion tons reduction required to attain a 50-50 change of curbing global warming at 2°C by that date.

In conclusion, a 2°C warming above pre-industrial levels might be unavoidable if more drastic measures are taken as soon as possible. But what happens if the Earth warms up by 2°C?

While scientists say that a 2°C warming is the most Earth can tolerate, that is not to say that significant changes will not be made to the planet as we know it. A temperature of 2°C above pre-industrial levels is believed to be the point of no-return, meaning that climate change that occurs after it is irreversible. This warming would mean the destruction of the majority of coral reefs, as well as glaciers and the Greenland ice-cap. The two latter would imply sea levels rise of up to a meter by 2100, which would displace 10% of the world’s population, according to an article by Sky News. Further research on the melting of the Greenland ice-cap suggests that irreversible melting will occur at 1.2°C, as the region is warming 2.2 times faster than the rest of the world. At this rate, the Greenland ice-cap would have melted entirely in 140 years, submerging coastal cities around the world, like Manhattan, Bangkok and Hong Kong.

Top: Extent of multiyear Arctic Sea Ice Age in 2012. Bottom: Extent of multiyear Arctic Sea Ice Age in 1980 - Photo Credit: Wikipedia

Moreover, mountainous regions would see more landslides as the permafrost in them melts. This would mean that those who currently depend on glaciers for water supply would be displaced, along with the hundreds of millions who depend on the water these glaciers and mountain creeks feed to massive rivers. The rivers themselves would be at risk, as the rise in global temperatures would cause them to shrink and finally vanish. As water supplies vanish, food production would be greatly affected. For example, in summer 2003 European farmers lost an estimate of $12 billion due to the heat wave.

A reduction of 80% on the surface area of Urmia Lake has threatened the food production and water supply of people who live in the area - Photo Credit: Wikipedia

The implications of these changes for mankind encompass a never before seen humanitarian crisis. Hundreds of millions of people would scramble for refuge away from the flooded coasts and humanity as a whole would endure water shortages and famine due to the scarcity of resources. Global warming would make temperatures currently considered as extreme a common occurrence and heat waves would be of Saharan intensity. This means that even in average years, people would die due to heat stress, especially in places with currently mild temperatures, where people are underprepared to face the heat. In addition to the deaths caused by the aforementioned factors, the proliferation of infectious diseases would lead to a massive loss of human lives.

A warming of 2°C over pre-industrial levels would slow and eventually stop plant growth. Furthermore, the remaining plants would emit carbon dioxide instead of absorbing it, so the current carbon sinkhole humanity relies on might turn against it. Other feedback mechanisms would face the same fate. As poles, ice-sheets and glaciers melt, their reflective surface would be replaced with dark water, which absorbs energy instead of reflecting it and thus further increases the global warming.

Finally, changes in climate conditions and geographical regions would cause ecosystems everywhere to unravel and species to fall out of synch, leading to one third of all species to face extinction by 2050.


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