The terrifying truth about climate change
For a couple of days we were bathed in glorious sunshine. Northern Ireland did not quite reach the record temperatures (20.3C) recorded in Wales but it was still warm enough for shorts and bare torsos. All this in February.
Some just relaxed and enjoyed it, but the hot spell also provoked a much needed debate about extreme weather incidents and their link to climate change. Sadly, like so many areas of public debate misunderstandings and misrepresentations are more common than insights.
Scope attempts to shed some light on the complex field of climate science.
Is climate change really happening?
Yes. The current global average temperature is 0.85C higher than it was in the late 19th century. Each of the past three decades has been warmer than any preceding decade since records began in 1850. An increase of 2C is the threshold at which climate scientists predict a high risk of catastrophic consequences to the environment, which we previously explored here. On our current trajectory we will reach that by the end of this century, with some scientists saying we are already past the point of no return.
Has it caused devastation before?
Yes. The prospect of a climate apocalypse seems implausible to many. Yet it has happened before and will happen again. To deny the possibility is to deny science. The fact is that humans have only been able to exist on the planet for a tiny fraction of its history.
We are currently in what geologists term the Quaternary Period which runs from around 2.8 million years ago to the present. This period has been characterised by long periods of Ice Age lasting around 100,000 years a time interspersed with shorter periods (10,000 to 60,000 years) of warmer weather.
For long periods Ireland was covered in ice sheets several hundreds of metres thick. When they melted they left behind the drumlins we see across southern Ulster today. Archaeologists tell us that the first signs of human colonisation of Ireland are from 8000 BC. So our presence here only goes back 10,000 years. Ireland was one of the last places in Europe to be occupied by people and in that sense is a very young land.
To somehow suggest that climate change can’t happen is to deny the very presence of the undulating landscape that surrounds us.
Incidentally it is 11,000 years since the last Ice Age. Glaciation will return perhaps in a thousand, maybe in tens of thousands of year. Unless scientists find a way to stave it off Ireland may already be half way through its existence as an inhabited part of earth. Current global warming is the immediate concern, if we overcome it the next challenge may well be another deep freeze.
Given that climate change is a reality, what is causing the earth’s temperatures to rise?
Several gases have the effect of trapping the sun’s heat in the atmosphere, stopping it from leaking back into space. These include carbon dioxide, methane and nitrous oxide. This is known as the Greenhouse Effect
All these gases occur naturally and there have been massive increases before. During the Cretaceous Period (142 – 65 million years ago) greenhouse gases rose to between four and ten times their current levels. The sea rose to around 300 metres above current levels. As a result Ireland and most of Western Europe was under very warm water (around 28C.)
What is the evidence to suggest that humans are responsible for the current rise?
In the case of carbon dioxide, for example, its levels in the atmosphere have risen by 40% since pre industrial times. We produce it when we burn coal and oil and gas. We compound problems by deforestation. Trees trap carbon dioxide, reducing levels in the atmosphere. When we chop them down we remove this beneficial effect and simultaneously the carbon stored in the trees is released into the atmosphere, exacerbating the greenhouse effect.
It follows that reducing or preferably eliminating our emissions of greenhouse gases will, over time, help stabilise global temperatures.
Are extreme weather symptoms of climate change?
This leads us back to our lovely weather and raises the question of whether it is a symptom of climate change.
The average maximum daytime temperature in Northern Ireland is 7C. It follows that this average temperature is higher than it was in the 19th Century so it, in itself is evidence of global warming. However we experienced temperatures of 15C. And this time last year we were in the grip of the Beast from the East which saw temperatures 20C lower.
Both last February’s freeze and this years warm spell are examples of extreme weather conditions. There have always been fluctuations in the weather. But are they connected to climate change?
The latest evidence suggests that they are. In 2004 a group of British scientists first established the link. We now know that extreme weather events, like storms and floods and heatwaves are occurring with increasing frequency and that this is connected to global warming. But whilst the statistical evidence is clear, actually proving precisely how individual localised events are caused by the warming planet are proving elusive.
It is also dangerous to jump to conclusions about climate change off the back of an individual extreme event. President Trump illustrated this perfectly earlier this year. His response to the ice storm that swept America was to tweet: “Ice storm rolls from Texas to Tennessee — I’m in Los Angeles and it’s freezing. Global warming is a total, and very expensive, hoax!”
Climate change may be happening dangerously fast in scientific terms but in terms of human experience it is slow. And wild fluctuations in temperatures, including extreme cold spells are also symptoms of this gradual warming process.
Those who are sceptical about the increasing frequency of extreme weather in Northern Ireland should take a look at the work of Climate Northern Ireland. It charts 120 separate incidents here since 2000. These include severe floods, heatwaves, freezes, destructive winds and devastating storms.
To conclude …
Climate change is the biggest issue for humanity. Not just over the next few decades as we battle to arrest global warming and not just for our generation either, but for all generations to come. The history of the planet suggests that our survival on earth is much more precarious than we like to think. Understanding how to limit our own damage to the planet is only part of it. The earth has been uninhabitable for far, far longer than we have been able to live here. It will be so again. What are we going to do about that?
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