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  • Writer's pictureArchie Milligan

A Three Degree World: What will it look like for us?

Children born today are up to seven times more likely to face extreme weather than their grandparents.


What are the chances of a three degree world?


Climate scientist Dr Joeri Rogelj of the Grantham Institute has spent a decade modelling future climate scenarios for the United Nations. Using models that represent our most sophisticated knowledge of climate change, he has produced projections showing that under current policies we have a 1 in 4 chance of reaching three degrees Celsius of warming by the end of the century.


Our best estimate for global temperature rise by 2100, if all climate pledges are kept, is two degrees. However, despite these efforts there is still a 1 in 20 chance that we get three degrees Celsius of warming instead.


Okay, so what are the implications?


A three degree world would have numerous and profound effects for all people across the globe. However, to speak broadly, we can split them into four interdependent groups: heat, sea level rise, flooding and societal effects.


Heat Effects


Regarding heat effects, dry seasons are already becoming longer and more severe in many parts of the world. In the Central American Dry Corridor, made up of Costa Rica, Nicaragua, Honduras, El Salvador and Guatemala, severe droughts are now four times more likely than they were last century. In a three degree world, annual rainfall in the region could drop by up to 14%.


Nearly two thirds of all smallholders in the Dry Corridor now live in poverty, and while this cannot be attributed solely to climate change, the effects of droughts and severe food shortages have deepened their crises.


These effects would, of course, not be limited to Central America. At three degrees of global warming, over 25% of the global population could experience extreme droughts for at least one month of the year. While Northern Africa could experience droughts that last for years at a time.


In addition, more regions will begin to experience deadly wet bulb temperatures: conditions of 100% humidity and high temperatures of 35 degrees or more. The high humidity makes it impossible for us to cool ourselves down and a high temperature that exceeds the body's natural skin temperature can become fatal.


Jacobabad in Pakistan and Ras Al Khaimah in the UAE have already registered deadly wet bulb temperatures. We can expect that in a three degree world, more of the tropics, the Persian Gulf and parts of the United States and Mexico could all reach this level.


Sea Level Rise & Flooding


By 2100, global sea levels could rise by half a metre from 2005 levels. This is critical, as 10% of the world’s population live on coastline that is less than 10 metres above sea level. Cities in these low lying areas, such as Lagos in Nigeria would be especially badly affected with up to a third of the population being displaced.


In Fiji, rising waters have already begun affecting people’s lives, as previously inhabited land has been lost to the sea. Along with the obvious dangers of higher sea levels, many coastal nations such as Myanmar and the Philippines would experience more storm surges, increasing the threat to life.


In the Bola district of Southern Bangladesh, heavy rainfall and Himalayan melt water has caused rivers to swell, washing away the homes of many. Those who have lost their homes and livelihoods have been forced to migrate, often into slums outside cities such as Dhaka.


However, cities tend to magnify the climate effects. They are hotter than the area around them, they are generally more vulnerable to flooding and the denser populations mean disasters in cities can be much more dangerous.


In the case of Dhaka, days that approach 40 degrees Celsius are now being reported, along with wet bulb temperatures. These conditions can become incredibly dangerous for the increasing number of inhabitants of the city’s slums.


Societal Effects


There are myriad societal effects driven by changes in our environment and behaviours. These include the disruption of food security, changes to established migration patterns, increasingly dense populations in and around cities and escalating competition for scarce resources.


There are 600 million smallholders (small scale farmers) around the world and of this number, those with under two hectares of land account for approximately one third of the global supply of food. Rural parts of the world suffer disproportionately from the effects of climate change, meaning that these smallholders are especially vulnerable.


The undermining of food security is evidenced by the effects of flooding and droughts on crop yields in regions such as Bangladesh’s Bola District and the Central American Dry Corridor. If crops, livestock and villages are destroyed by flooding or drought, it is incredibly difficult to survive and rebuild.


Many people are instead forced to migrate, often to urban areas. Currently, half of the world’s population lives in cities, with almost one third of them in slums. As this migration increases, there will be more competition for fewer resources.


The demand for food will increase in urban centres while the supply of food, especially from smallholders will likely decrease. While control over water, which is already a highly contested resource, will become increasingly contentious on the local and international level.


Then, how do we best deal with a three degree world?


If we reach this precipice, we can adapt on the regional and local level by building sea walls, diversifying agriculture and improving air conditioning. However, all these measures and any others we can think of would be designed to reduce our suffering, rather than to eradicate it.


The best way to deal effectively with a three degree world is to avoid reaching it at all costs. If, collectively, we hold carbon emitters accountable and take the bold actions necessary to reduce carbon emissions and slow climate change, then we can do justice for our future generations.


By Archie Milligan ©

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