Nerilie cutting up an ice core from James Ross Island, 2008.
Nerilie cutting up an ice core from James Ross Island, 2008.

By Claire

Undoubtedly, the sexiest palaeoclimate proxy are ice cores. Most people have heard of them, most people believe them and they form an important foundation for our understanding of the natural variability of the Earth’s climate in the past.

Last week, a paper (published in Nature Geoscience) was written by our very own super scientist, Nerilie Abram, based on work she did while at the British Antarctic Survey. Nerilie and a team of scientists went to James Ross Island on the Antarctic Peninsula in 2008 to drill a 354 metre long ice core, spanning the last 1000 years. 

Within this ice core are visible melt layers, caused by annual melting of the snow cover during Summer. Ice cores are full of tiny bubbles that are trapped within the ice as snow is compacted under the weight of new snowfall. Melt layers are visible as largely solid layers of ice, where the bubbles have been removed due to the snow becoming liquid. Over time, a pattern of bubbled and solid layers form within the ice core, providing a history of ice melt at this site over time. Thicker solid layers indicate larger melt events.

An ice core record of temperature and surface melt over the past 1,000 years at James Ross Island (JRI), Antarctic Peninsula. Upper panel, the thin green line represents average temperature at the site expressed relative to the average between 1981 and 2001. Lower panel, the thin red represents snow melt at the surface, expressed in per cent of annual snowfall. Thick lines are smoothed versions of the annual data. Dashed lines show the 1981—2001 averages. Figure adapted from Abram et al.
An ice core record of temperature and surface melt over the past 1,000 years at James Ross Island (JRI), Antarctic Peninsula. Upper panel, the thin green line represents average temperature at the site expressed relative to the average between 1981 and 2001. Lower panel, the thin red represents snow melt at the surface, expressed in per cent of annual snowfall. Thick lines are smoothed versions of the annual data. Dashed lines show the 1981—2001 averages. Figure adapted from Abram et al.

Nerilie (and others) were able to re-create a melt history for this ice core for the last 1000 years by counting and measuring these alternate melt and snow layers.

What they found, is that recent melting at this site is almost 10 times greater than it was 1000 years ago, at the beginning of this ice core, with this rate increasing the most over the last 50 years.

In addition, it was found that there is a temperature threshold at which melting of the ice increases dramatically.

“What that means is that the Antarctic Peninsula has warmed to a level where even small increases in temperature can now lead to a big increase in summer ice melt. This has important implications for ice instability and sea level rise in a warming climate,” said Dr Abram.

What I found particularly interesting though, was the response this paper received in the comments section of newspapers and blog sites.

Some of my favourite definitely come from this Huffington Post Article.

“1000 years ago was the dark ages. No science – just superstition. Farenheit was not even born, so where did this “data” come from? It’s an estimate, Jim. “1000 years” is just used for dramatic effect. Unfortunately, superstition still makes for better copy 1000 years later.”

“The above report is totally bogus.
Clearly, global “warming” is moderating and has been slowing down since at least 2000. In another ten years, it will be history.
http://www.reuters.com/article/2013/04/16/us-climate-slowdown-idUSBRE93F0AJ20130416

“Who was there to measure ice melt 1,000 years ago? This whole issue about global warming is liberal nonsense and has been admitted to by.the perpetrators that the data was manipulated. It a big lie, a hoax. Find something read to worry about like; Why won’t Obama do anything to create jobs?”

“I thought the Increase in Temps was causing Evaporation and a reduction in Ocean and Lake Levels ? Really Hard to keep up with all the Spin…and who was keeping records 1,000 years ago ? Aborigines or Indians ?”

 

I’ll stop myself there, but there are literally hundreds of comments similar to these in response to this blog post and others that were also written on this research.

climate-conspiracyI think my point really ties back to a rant I had recently, that climate scientists DO in fact know what they’re doing, and they’re not part of some giant conspiracy to take over the world through fear mongering.

This in response to a scientific article that clearly outlines its methodology, results and conclusions for people to read (although you do need a subscription to the journal to access it – another rant for another time…). The authors have not made any conclusions that aren’t supported by data shown in the paper, and yet, people seem to be offended by this research.

Why is that? How can something so objective be so offensive?

I think it comes down to the fact that this paper, when seen in the context of the hundreds of other peer reviewed papers that show that current levels of warming and CO2 concentrations are not part of the natural variability of the climate system, require drastic action to be made. Our lifestyles and in fact, the whole basis for our economy needs to shift and naturally, people are resistant to that change.

Just because you don’t like it, doesn’t mean it’s not true.

You can access a really interesting explanation for the implications of Nerilie’s paper, alongside another ice core paper recently published on The Conversation’s website.