It’s getting hot, and I don’t just mean in Qatar. There have been a number of global temperature records that have been broken recently and the heat is showing no sign of letting up. Last year was the warmest on record; the temperature was approximately 1C above the pre-industrial average. This is the period between 1880-1899, just before humans started pouring vast amounts of carbon dioxide and other gases into the atmosphere. This average is used as a baseline to see how much human activity has increased the temperature of the planet.
The Intergovernmental Panel on Climate Change (the IPCC) recommends that the global temperature should not be allowed to increase more than 2C above the pre-industrial average. It is thought that an increase of more than this would bring catastrophic changes to sea levels, food production and water reserves. Even a 2C rise is likely to result in a dangerous increase in droughts, floods and heatwaves, but it is thought to still be tolerable for the majority of plants and animals on the planet. Considering that global temperatures have already risen to 1C above the pre-industrial level, and globally we are still pouring vast amounts of carbon dioxide into the atmosphere, this aim is now looking ludicrously optimistic.
Temperature records have continued to tumble this year too. Across the globe, the average surface temperature in January was 1.15C warmer than the average temperature for the month. This is a larger margin than had ever been seen before, in any month. A new record was set, but one that didn’t stand for long. Just one month later, February 2016 was 1.35C higher than the February average, smashing the January record into smithereens.
Even without the activities of man, global temperatures would be expected to be higher than average at the moment. The global measurements are always enhanced during an El Nino event. El Nino is the name given to the warming of the surface waters of the Pacific Ocean. It’s a natural phenomenon which happens every two to seven years, and has a knock on effect on the weather around the planet. Southern Africa and Australia often experience a drought, whereas Argentina and the southern US states are usually inundated with rain.
As well as disrupting the weather in many parts of the globe, El Nino also releases large amounts of heat from the ocean. This heat results in the enhanced global temperature readings. At its peak, the current El Nino was one of the strongest ever recorded, so it would be expected that it would have a fairly large impact on the global temperature readings.
However, El Nino alone cannot be held responsible for the entire increase in temperature. The years 2011 to 2015 was the warmest five-year period on record, but El Nino only emerged in 2015, so cannot have had an effect in the climate in the preceding years.
The only thing that could account for such a dramatic rise in temperature is the huge increase in our atmosphere of carbon dioxide and other gases, known as greenhouse gases. The effect of greenhouse gases is not a new discovery. For over 120 years it has been known that they trap the sun’s heat within our atmosphere and increase the temperature, but despite that, vast volumes of them are pumped into the atmosphere every year.
The greenhouse gas that accounts for approximately three quarters of the warming caused by human activity is carbon dioxide. For this reason the exact volume of the gas is tightly monitored. The official measurements for this are taken at Mauna Loa Observatory in Hawaii. It might sound like a strange place to take readings, but it is thought that taking measurements on the slopes of a volcano, surrounded by many kilometres of bare lava, will eliminate the problem of the gas being locally absorbed or emitted by nearby plants or soils.
This remote location tells us that the amount of carbon dioxide in the atmosphere is still rising. In March last year, the reading reached 400 parts per million for the first time ever. Over 2015 as a whole, the measurements jumped by 3.05 parts per million, the largest year-to-year increase since records began 56 years ago.
Again, part of this increase will have been due to the El Nino conditions in the Pacific. During El Nino, plants respond to the changes in the weather, and there are also a dramatic increase in the number of wildfires. This leads to an increase in carbon dioxide, but not all of its increase can be brushed quite so neatly under the carpet.
The amount of carbon dioxide in the atmosphere is still increasing, and therefore the amount of heat trapped in our atmosphere has to increase as well. This will lead to a rise in the number of heatwaves, droughts and floods across the globe. We appear to be hurtling towards the agreed maximum increase of 2C at an alarming pace. My son is only one year old. I wonder what changes he will see during his lifetime.