Ice Age

We may not realise it, but we are currently living in a Glacial Epoch. Due to the brevity of human history, having the Earth’s poles covered in ice seems normal, but it is actually a unique occurrence in the very long life of our planet. When we think about it this way, it becomes clear that there is a very fragile balance, which determines our climate, and consequently, life as we know it. It would take very little to permanently alter this state of affairs, which would have disastrous consequences: the six degrees of difference in temperature, which the Gulf Stream could potentially generate, would change the climate conditions of the entire planet. 

If Greenland were not located in its path, the Gulf Stream would warm the Arctic by six degrees, and the thin sheet of ice floating on the surface of the Arctic Ocean would disappear. This would change the climate of the temperate region of the entire northern hemisphere. Today, thanks to the shiny white surface of the ice, solar energy is reflected, and the entire polar region remains cold. If the ice were to start melting, the surface of the ocean would be liquid and dark, so the sun’s heat would be absorbed, and the warming process would spread to the entire Arctic region. 

It is important to remember that climate does not come from the sky, but from the sea, because it is the result of a complex and stable system of moving currents. The warm water of the Gulf Stream flows over the ocean surface until it meets the western edge of the North Atlantic, moving thirty million cubic metres of water per second. This ‘river’ is part of a system of currents, which flow from the tropical Pacific around the Cape of Good Hope, and which store heat for much of this long journey. The warm water is less dense than the cold water, so it forms a surface current, which gradually becomes warmer and warmer. In addition, this body of water is also very salty, because the collected heat and the surface position lead to evaporation. Having made it as far as the North Atlantic, the current gives up its heat to the winds that blow from west to east at those latitudes, carrying the heat towards Europe. At this stage, after cooling down, the water mass descends into the ocean depths, due to the density and weight of the high salt content, and completes the cycle to flow back into the North Pacific.

If Antarctica were to melt, cold water with a low salt content would be injected into this perfect cycle, destroying its balance, and dramatically changing the climatic conditions we are used to: Europe’s climate would be similar to Vancouver’s, while Vancouver would have temperatures like those we find in Ireland today. 

Due to what scientists call ‘positive feedback’, small changes in the Earth’s heat balance can have significant effects on the global climate. Since we are living in a relatively warm phase of what is effectively a mild ice age, it would only take a few degrees to cause a return to the conditions of a harsher, destructive ice age.