Climate change is without doubt one of the biggest threats, if not the biggest threat, to the survival of our civilisation as we know it today. That may sound dramatic, but we only need look at the growing number of natural disasters which are happening around the world each year as a result of extreme weather conditions.
These disasters, from floods to droughts, hurricanes to forest fires, are nothing new of course. They were almost certainly happening long before human beings walked the Earth and no doubt will always happen. The difference is the frequency and the extremity of these events. The real threat however is not from the headline grabbing extreme events but from the gradual changes. The rising sea levels that will eventually engulf entire countries and cause mass migration, the droughts in some areas that will make it impossible to grow food and the floods in other areas that will make them uninhabitable.
What Causes Climate Change?
An increase in “greenhouse gases”, in particular carbon dioxide, in the Earth’s atmosphere massively contributes to climate change. Carbon dioxide works like insulation in your home. Imagine you put the central heating because you’re cold. The room won’t get warm immediately; the heat from the radiators will take time to transfer to the surrounding air molecules. What’s more, some of the warmed air will escape through windows, walls and the ceiling, though hopefully at a lesser rate than it is being heated. Eventually you will be able to sit a few metres from the radiators and still be warm.
Now imagine the ceiling and walls were removed. No matter how long you had the radiators on, you would never get warm unless you stood right next to them. This is because the warm air is not confined and is able to move away from you more quickly than the radiators can heat it.
Now let’s put the walls and ceilings back and make the room completely airtight, with no doors and windows and with walls so well insulated that no heat can escape. Further, let’s imagine that the thermostat is broken and the radiators are stuck at on (just like the Sun can’t be turned off and has no thermostat). The room would quite quickly become unbearably hot and in fact would eventually be at the same temperature as the water in the radiators.
Carbon dioxide acts like the walls and ceiling of your house. We need a certain amount in the atmosphere otherwise all of the heat would escape from the Earth and we would freeze, but if we have too much we will overheat, and the more there is, the more we will overheat. The Earth’s ecosystems are in a delicate balance and even an increase of a couple of degrees in average temperatures can have a dramatic effect.
What Causes Greenhouse Gases to Increase?
As mentioned above, the most abundant greenhouse gas is carbon dioxide. Every living thing is made of carbon. Life on Earth would simply not exist without it. When living things, such as trees, die and rot they deposit carbon in the ground, which becomes trapped. As layer upon layer is deposited it turns to coal, oil or gas which we collectively call fossil fuels.
When these fossil fuels are burned, to produce energy, the trapped carbon is released into the atmosphere as carbon dioxide. Since the start of the industrial revolution about 250 years ago these fossil fuels have been burned at such an alarming rate that deposits which took hundreds of millions of years to build up have been almost totally exhausted.
In addition to the burning of fossil fuels, the destruction of the rainforests and the pollution of the oceans mean that less carbon dioxide is being absorbed naturally.
What Will Happen to the UK Climate if Global Warming Continues?
Ask people in the UK if they are worried about climate change and many will glibly reply that they would love it to get a few degrees warmer. Ironically the reality could be quite the reverse. It is true that it will become warmer in the short term, causing extreme heat waves which will lead to water shortages and will put risk groups such as the elderly and the very young at risk, but that effect may only be temporary. As temperatures in the northern hemisphere rise more and more of the polar ice cap will melt, flooding the northern Atlantic with extremely cold, freshwater.
This influx of new water will potentially do two things; first, it will raise sea levels to the point where coastal regions of the UK will be completely flooded. Whole towns and cities could potentially be lost forever and seaports which are vital to trade and supply will be gone. Another, perhaps more damaging effect however could be the disruption to the North Atlantic Drift.
The Gulf Stream and the North Atlantic Drift
The Gulf Stream is an ocean current which flows from the warm waters of the mid Atlantic ocean around the Caribbean north, blown by the Trade Winds. As it moves north it splits into branches, one of which, the North Atlantic Drift, flows past northern Europe and the UK. As winds cross this current on the way to our shores they are warmed by the warmer water it brings and this is the reason why our climate is so much less harsh than other areas of the world on similar latitudes such as Canada or Siberia.
As the warmer water moves further north it cools and as it cools it sinks and travels back south to the mid Atlantic where it is warmed, rises, is blown north and so the cycle continues. As the icy water from the melting ice caps flows south however it is though that it will cool the water prematurely and thus stop the current.
Should this happen it will plunge the UK, together with Scandinavia and other parts of northern Europe, into an ice age. Average temperatures will drop by up to 10 degrees Celsius and our climate will come to resemble that at the poles.
What Would an Ice Age Be Like?
The UK would potentially be covered, year round, in ice. Apart from the obvious disruption to transport networks etc, little or no crops could be grown to provide food and our farm animals would die out, either through exposure or lack of food.
Our ports, which as an island we rely very heavily on, would be frozen and not accessible by ships. We would be unable to receive deliveries of oil or coal, vital fuel for our power stations, which we would need all the more in such freezing temperatures. The North Sea would be completely frozen making it difficult if not impossible to obtain oil from there. It is difficult to see how, in those conditions, a modern society could survive.
