The Earth’s climate is changing. Or is it?
While most people can agree that the climate is changing – it always is – there are differing opinions about how and what’s causing it. Scientific and non-scientific evidence indicates there is man-made climate change happening and that the most largest contributing factor is the emission of greenhouse gases, such as CO2, causing global warming.
But how clear-cut is this case, really? Is there any merit to the sceptics’ claims that there is an outbreak of climate hysteria going on, or are they just misinformed and overly suspicious?
In this article, we examine the facts and myths of climate change and give you the sources, for further reading.
1. The global temperature is rising
It is a that the average global surface temperature has risen 1.62 degrees Celsius since the end of the 19th century. It is also a fact that most of the change has happened during the last 35 years, which coincides with the increasing amount of greenhouse gases in the atmosphere.
The temperature is not actually fluctuating, as some claim. It’s been on a steady rise and in fact, the trend has been accelerating.
CONFIRMED: global warming is real!
2. Polar ice sheets are shrinking
Ice sheets fluctuate naturally and they have been doing so, naturally, for thousands of years. However, nothing in nature can explain the extreme rate of polar ice caps shrinkage that scientists have observed during the last decade. Especially in the Arctic, the trend is clear.
The ice caps are melting at an accelerated pace and it does not have time to re-freeze during the winters. As the development continues we will start seeing severe secondary effects on a global scale.
CONFIRMED: polar ice caps are getting smaller!
3. Glaciers are retreating
While polar ice caps may be difficult to follow, more people are able to observe glaciers retreating and getting smaller.
Glaciers can shrink for two reasons:
- Reduced snowfall in winter
- Warmer weather during the summer
Currently, we can see both of these things happening simultaneously, and everywhere in the world glaciers are shrinking. Glaciers are great heat sinks and reflect sunlight back into space. Their retreat causes accelerated warming everywhere else.
4. Oceans are getting warmer
The oceans are vast and the water in them can absorb enormous amounts of energy with only small changes in temperature. That is why it’s so alarming, and telling, that ocean temperatures have been rising steadily since the 1940s.
Although the temperature rise is minuscule, at 0.13 degrees Celsius, this represents a huge change considering the sheer mass of water involved.
If it weren’t for the oceans, global warming would be much more severe and obvious.
CONFIRMED: The oceans are getting warmer
5. Sea levels are rising
In 2014, average global sea levels were 6.6 cm above the 1993 averages, according to the NOAA, and the 1993 level was the highest recorded average ever, at the time.
On average, sea levels continue to rise around 3 mm yearly, something which is causing big problems around the world. Why are sea levels rising?
Scientists point to two reasons:
- Thermal expansion – As the oceans get warmer the water expands, as do all materials when you heat them.
- Ice melting – Polar ice caps, glaciers and other ice masses are retreating, contributing more water to the oceans.
CONFIRMED: sea levels are rising.
6. Decreased snow cover
The evidence is clear. According to studies by NSIDC, snow cover is decreasing every year. While this doesn’t directly affect sea levels, it must be caused by something.
At the climate gets warmer more precipitation falls as rain instead of snow and the snow that falls does not accumulate as much as it used to. Those of you into winter sports will have already felt the impact.
CONFIRMED: levels of snowfall is decreasing.
7. More extreme weather
According to scientific evidence and data compiled by NASA, the number and intensity of severe weather events have increased since the 1950s, with one exception.
The number of record low temperatures have steadily decreased. This doesn’t bode well if you want to make the case that climate isn’t changing, because it obviously is and not in a good way.
With global warming, we’re seeing more extreme weather events storms and more precipitation than ever before.
CONFIRMED: The increase in extreme weather events is clear.
8. Ocean acidification
While the detailed chemistry is a bit much for us to cover here, it isn’t exactly rocket science. When the greenhouse gas carbon dioxide (CO2) is absorbed by water carbonic acid is formed, making the water acidic.
It is the same thing as happens in carbonated soft drinks, only it’s happening in our oceans. Since the beginning of the industrial revolution, the pH level of the oceans surface water has dropped by 0.1.
Exact numbers aside, this is a substantial change that has real effects on life in our oceans.
Will there be any fish in the oceans of tomorrow? Well, we don’t know but if pH levels continue to drop it may have a huge impact on wildlife at sea.
CONFIRMED: the ocean is acidifying.
9. Scientists don’t agree!
No, they don’t. Actually, scientists usually do not agree.
That’s how scientific progress is made. Only, as far as climate change is concerned, scientists actually do agree to an alarmingly high extent, around 98%.
There is actually a consensus that the climate is changing and that, to a large part, it is happening because of human activity in general and the emission of greenhouse gases in particular.
BUSTED: Scientists do agree.
10. It's the sun's fault
Amongst climate change deniers it’s a popular refrain to blame the sun for global warming. Yes, solar activity has a huge impact on our climate and the temperature of the earth, but it isn’t enough to explain what we’re currently seeing.
This has been studied by the IPCC among others and the conclusion is always the same: the sun does contribute to climate change, but the variations in solar activity cannot explain more than 10 per cent of the changes in temperature that we are observing.
BUSTED: it's the sun's fault.
Science is never settled. This is as true for climate science as much as anything, but it doesn’t mean that we don’t know anything about climate change and its causes.
Scientists know a lot more today than they did just a few years ago and they will continue to learn more in the future.
This doesn’t change the fact that the climate is changing and that we are contributing to it in a substantial way. We know this already and we’re gaining better understanding every day.