We have left our traces all across the earth, even where we cannot see them.
The work of man
Klassekampen, 26 January 2018
Frozen iguanas fell from the trees in Florida! How can climate change be true? Every winter it's the same story. As soon as a single snowflake falls from the sky, climate skeptics will elbow each other out of the way to declare that the earth isn't warming.
But while the east of the US could go skiing, the west saw extremely high temperatures. In Alaska it was 8.7 degrees Celsius warmer than normal last December – a new record. And in Europe there were also big differences this winter, such as two weeks ago: while the south of Norway had perfect snow, it was so warm on Svalbard that it rained. The sun will not come back for another couple of weeks.
These extreme differences were caused by changes in the jet stream. This very strong wind, at high altitude in the atmosphere, normally blows from west to east, and separates cold arctic air from warmer air in the south. This is also known as the polar vortex. In the last few winters, this wind has started to wobble in a north-south direction. In some areas this means that arctic air is blown far to the south, in other areas there is abnormally warm air blown to the north.
The changes in the jet stream have to do with climate change. The more frequent occurrence of both cold and warm weather extremes is a typical example of this. The scoffing at exceptional snow situations by climate deniers is misleading and meant to make you doubt the reality of climate change. A tip to stay immune: the next time a climate denier points out that it is extremely cold somewhere, I bet you can also find news about extreme heat elsewhere.
Nevertheless, climate deniers continue to raise doubts. The earth is supposedly too big, and the influence of man too small, to influence something like the climate. But anyone who has traveled the world a bit, or looks at Google Maps, knows that this isn't true. The influence of man (now 7.6 billion individuals) is noticeable almost everywhere.
You mean roads, cities, and towns? No, if you add those all up, you end up with just one percent of the global land surface. We need much more of the planet's surface for our food. The area required for livestock and crops used for grazing and feeding covers an enormous area: as much as North and South America together. Add to that the rest of our agriculture, and you end up with one third of all the land in the world. If you look at the enormous influence that we jointly exert on our planet, it is impossible to maintain that we cannot influence our climate.
That amount of CO2 will remain in our atmosphere for centuries
A recent study in the journal Nature tried to figure out how big that influence is. Using satellite data and detailed mapping, they showed how much carbon is stored globally in vegetation such as plants and trees - and how much would have grown without human intervention. It turned out that we have halved the amount of vegetation. In absolute figures, this difference equals the same amount of CO2 as 50 years of fossil fuel emissions. Half of this comes from deforestation, including what had already disappeared before the industrial revolution. But that is nothing compared to the deforestation of the last decades.
Much of this is already known, but this study added that the way in which we manage the remaining bits of nature is not optimal for storing carbon. Land use such as the selective logging of forests and grazing has been responsible for approximately as much carbon loss as deforestation.
Our land use has major consequences for our atmosphere and climate. Nevertheless, the main prize still goes to the CO2 emissions from fossil fuels. Just to give an example: more than a billion cars drive around the world today, and this number is increasing rapidly. The idea that our influence on the atmosphere is small is therefore naive. Moreover, the increase in CO2 in the atmosphere has been recorded in detail since the 1950s. Natural fluctuations are nothing compared to the rising trend we have created.
That amount of CO2 will remain in our atmosphere for centuries – nature is not going to solve it for us. It's true that plants like some extra CO2, since it makes them grow faster. Not fast enough, unfortunately, to cancel out the unprecedented scale with which we pollute the atmosphere.
The influence of man on the atmosphere also means this: It does not matter whether a flower grows on an unreachable mountain peak in South America, or if a shrub is somewhere out on the vast tundra. We may not be able to reach those places – we have ensured that the plants out there will never grow the same again.
This text originally appeared in Klassekampen on 26 January 2018