What ice cores tell us about #ClimateChange #StopAdani #auspol 

This is what ancient, 3km long ice cores tell us about climate change

Cracks are seen on the Fourcade glacier near Argentina’s Carlini Base in Antarctica, January 12, 2017. Picture taken January 12, 2017. REUTERS/Nicolas Misculin – RTSW9RN

The speed at which CO₂ is rising has no comparison in the recorded past.

Image: REUTERS/Nicolas Misculin

There are those who say the climate has always changed, and that carbon dioxide levels have always fluctuated.

 That’s true. But it’s also true that since the industrial revolution, CO₂ levels in the atmosphere have climbed to levels that are unprecedented over hundreds of millennia.
So here’s a short video we made, to put recent climate change and carbon dioxide emissions into the context of the past 800,000 years.

The temperature-CO₂ connection
Earth has a natural greenhouse effect, and it is really important. Without it, the average temperature on the surface of the planet would be about -18℃ and human life would not exist. Carbon dioxide (CO₂) is one of the gases in our atmosphere that traps heat and makes the planet habitable.
We have known about the greenhouse effect for well over a century. About 150 years ago, a physicist called John Tyndall used laboratory experiments to demonstrate the greenhouse properties of CO₂ gas. Then, in the late 1800s, the Swedish chemist Svante Arrhenius first calculated the greenhouse effect of CO₂ in our atmosphere and linked it to past ice ages on our planet.
Modern scientists and engineers have explored these links in intricate detail in recent decades, by drilling into the ice sheets that cover Antarctica and Greenland. Thousands of years of snow have compressed into thick slabs of ice. The resulting ice cores can be more than 3km long and extend back a staggering 800,000 years.
Scientists use the chemistry of the water molecules in the ice layers to see how the temperature has varied through the millennia. These ice layers also trap tiny bubbles from the ancient atmosphere, allowing us to measure prehistoric CO₂ levels directly.

 

The ice cores reveal an incredibly tight connection between temperature and greenhouse gas levels through the ice age cycles, thus proving the concepts put forward by Arrhenius more than a century ago.
In previous warm periods, it was not a CO₂ spike that kickstarted the warming, but small and predictable wobbles in Earth’s rotation and orbit around the Sun. CO₂ played a big role as a natural amplifier of the small climate shifts initiated by these wobbles. As the planet began to cool, more CO₂ dissolved into the oceans, reducing the greenhouse effect and causing more cooling. Similarly, CO₂ was released from the oceans to the atmosphere when the planet warmed, driving further warming.
But things are very different this time around. Humans are responsible for adding huge quantities of extra CO₂ to the atmosphere – and fast.
The speed at which CO₂ is rising has no comparison in the recorded past. The fastest natural shifts out of ice ages saw CO₂ levels increase by around 35 parts per million (ppm) in 1,000 years. It might be hard to believe, but humans have emitted the equivalent amount in just the last 17 years.
Before the industrial revolution, the natural level of atmospheric CO₂ during warm interglacials was around 280 ppm. The frigid ice ages, which caused kilometre-thick ice sheets to build up over much of North America and Eurasia, had CO₂ levels of around 180 ppm.
Burning fossil fuels, such as coal, oil and gas, takes ancient carbon that was locked within the Earth and puts it into the atmosphere as CO₂. Since the industrial revolution humans have burned an enormous amount of fossil fuel, causing atmospheric CO₂ and other greenhouse gases to skyrocket.
In mid-2017, atmospheric CO₂ now stands at 409 ppm. This is completely unprecedented in the past 800,000 years.


The massive blast of CO₂ is causing the climate to warm rapidly. The last IPCC report concluded that by the end of this century we will get to more than 4℃ above pre-industrial levels (1850-99) if we continue on a high-emissions pathway.
If we work towards the goals of the Paris Agreement, by rapidly curbing our CO₂ emissions and developing new technologies to remove excess CO₂ from the atmosphere, then we stand a chance of limiting warming to around 2℃.
The fundamental science is very well understood. The evidence that climate change is happening is abundant and clear. The difficult part is: what do we do next? More than ever, we need strong, cooperative and accountable leadership from politicians of all nations. Only then will we avoid the worst of climate change and adapt to the impacts we can’t halt.

Press link for more: weforum.org

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5 comments

  1. Unfortunately, there are some points that allow deniers to jump on. Firstly, even though sea level rise is occurring at an alarming rate. This is tiny in every day terms. An increase of mm is not able to be grasped by anon.Joe Bogan. Secondly, many / most predictions are using the turn of this century as their data line (for want of a better term). To people, that is a lifetime away. Third there is greed. No matter what is shown, people are only concerned when their pocket is not affected. Hopefully this will change. I have no answers to maggots like Dean, Cameron, Jones, Bolt who are out there squealing how CC is a hoax. Especially when they use the lack of sea level rise in Sydney Harbour and the alarms shouted from the roof tops by earlier climate change students like Tim Flannery and others like him. He had good intentions but his claims were so far over the top, they have given ammunition to the denial group instead of helping.
    My only come back is OK I have no answer to some of your points but that doesn’t mean because I have no answer that it is not happening but use your same logic on glaciers. Then I ask how are billions of people going to get fresh water once the glaciers have gone and regarding people like Flanery, they were only able to project using the data at that time and said data has now improved markedly. I would love for someone to help me out with the Sydney Harbour sea level non rise problem.

    Liked by 1 person

  2. In 1913 German archaeologists discovered what they believed to be the ruins of the Tower of Babel. Situated on the Euphrates River they were unable to commence further exploration because the base of the Tower was surrounded by deep water. Now, after the hottest, and dryest period of time since 1913, archaeologists have access because around the Tower the river has completely dried up, or receded. The only reminder is a few marshes.

    That terrifies me. There is no Planet B.

    Liked by 1 person

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