At last year’s COP21 summit in Paris one number was thrown around more than any other: two degrees Celsius, the agreed upon figure to which are supposed to limit global warming to avoid the most dire consequences of climate change. However, the way this figure is presented erroneously suggests that two degrees Celsius is the “safe” limit and that as long as we stay under it everything will be fine, while in fact if we come near or reach that figure our world will change very drastically in ways that are not conducive to our wellbeing. It’s important that society becomes aware that the two degree limit is not wiggle room we can abuse, but rather a situation that we should do everything in our power to avoid reaching. So what exactly do two degrees of warming look like?
Sea level rise: Scientists believe that two degrees Celsius is the tipping point for large ice sheets in Greenland and the Antarctic. Greenland’s ice sheet is already experiencing rapid erosion year after year, and while the ice sheets around the South Pole have remained more stable up until now, new research suggests that previously unconsidered active physical processes brought about by increases in atmospheric temperature could trigger rapid and drastic melting in the Antarctic. Disappearing ice sheets would add a significant amount of water to the seas and the oceans, and the same increases in temperature that would melt ice would also make the water itself expand. As we all know matter expands when it heats up, so through the combination of these two factors we could see sea levels rise by as much as 2 meters in a worst case scenario. If you live inland, far from the coast, 2 meters don’t sound like much but the effects would be huge. Coastal mega-cities like New York, Shanghai and Mumbai would be severely affected. A large portion of the global population concentrates in low lying, coastal regions, and 2 meter of sea level rise would displace hundreds of millions of people around the world.
Impact on food production: With the population of the world predicted to grow to over 9 billion people by mid-century, we will be needing more food than ever before to keep everyone fed. Certain areas in higher latitudes such as northern Europe, Russia, and the northern United States and Canada may see increased food production on account milder winters and longer growing seasons, but whatever gains these regions produce will likely be offset by losses elsewhere. The subtropics, like the Mediterranean region and Australia will experience significant declines because of loss of precipitation and drought, while increased temperatures will also make crops more vulnerable to pests and diseases. Yields from rain-fed crops in certain parts of Africa could decline by as much as 50% because of the conditions brought about by Climate Change. Furthermore, while growing seasons may become longer in certain areas, there appears to be a correlation between climate change and extreme weather events such as floods, blizzards and hurricanes. Although these events are rare overall, it is possible that more agriculturally productive regions also become more vulnerable to extreme weather, potentially increasing the volatility and the variance of crop production from season to season.
Heat waves will become the new norm: Europe’s summer of 2003 is now remembered as one as the worst heat waves the continent has ever experienced. Estimates place its death toll at somewhere around 70,000 people, and the conditions that caused it will cease to be a rarity with two degrees of warming. In fact, they will be the new norm – the hotter weeks of the summer will often average over 40º Celsius, meaning we will have to completely redefine what the concept of “heat wave” means. According to research by the Met Office, the likelihood of having incredibly hot summers could increase by a factor a 10. Surprisingly, the worst effects of this potential scenario are not the danger it represents to human health, but rather how it could activate a feedback loop that would make climate change even worse. Due to the dramatic increase in temperature in 2003, plant growth slowed and eventually stopped. Along with the oceans, plants are the world’s largest natural repository of carbon dioxide, and due to the unusually high temperatures of 2003 instead of absorbing carbon plants started to emit it. It is estimated that European plant masses output half a billion tonnes of carbon in 2003 as a result of the heatwave– if this became an every year happening the consequences would be dire.