the climate brief Accurate Reporting of Climate Science

Lonnie Thompson

Knowing how and why earth's climate has changed in the past is key to understanding the impact of human activity now and in the future. Last week, scientists gathered at the Geological Society in London to discuss earth's climate over the last 11,700 years - known as the holocene. We went along and listened to the discussions. Here's a quick look at what reconstructing earth's history is all about.

Climate proxies

In  new research published in Science Express, a team of scientists led by Lonnie Thompson of Ohio State University studied an ice core drilled from the Quelccaya Ice Cap in Peru, the world's largest tropical ice sheet. Unlike previous ice cores from the same area, each year of the core's 1,800 year lifetime is recorded in clearly defined layers. By examining the layers, the researchers can learn about the climate conditions in the region over past two millennia.

This is one example of what scientists call a climate proxy.Thermometers have only been measuring temperature directly since about the late 17th century. So instead scientists use natural recorders of temperature change, which can include seafloor sediments, corals, fossilised pollen on land, ice cores and tree rings.

The conference at the Geological Society centred around how proxies can be used to reconstruct various aspects of earth's climate over the holocene.

One talking point was a recent paper in Science by Shaun Marcott from the University of Oregon that used a range of climate proxies to reconstruct global temperature over the holocene.

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Are scientists, communicators and policymakers too preoccupied about whether people 'believe' in human-caused climate change or not? Polling by Carbon Brief shows that while people may not be sure whether humans are warming the planet, the majority still wants action now to abate climate change.

According to polling carried out for Carbon Brief by Opinium, 89 per cent of respondents said they believe climate change is happening. Only six  per cent said they did not believe the climate is changing.

But opinion was divided when it came to what's causing climate change. The majority - 56 per cent - said humans are causing the warming, but a significant number - around 33 per cent - believe it's mostly down to natural causes.

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People in the UK overwhelmingly trust scientists more than any other source to give them accurate information about climate change, according to a new survey. In contrast, politicians and social media come joint last on the list.

Scientists most trusted

According to a new poll conducted for Carbon Brief by pollsters Opinium , 69 per cent of those asked agreed that scientists and meteorologists are trustworthy sources of accurate information about climate science. Only seven per cent disagreed that scientists could be trusted to do this.

Next highest came 'green' charities such as Greenpeace and Friends of the Earth, and BBC journalists and commentators, with 39 per cent and 31 per cent respectively saying they trusted these sources. But these groups divided opinion - 23 per cent don't trust green charities, and 25 per cent think the BBC can't be trusted to provide accurate information. 

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Carbon Brief's poll has tons of interesting findings - some of them covered in this week's blogs. But as with any apparently new information, it's useful to put the results in the context of what we've seen before. How does the poll fit with what others have shown?

I'm going to pick on three places where it's interesting to compare the new poll with previous ones.

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In the final episode of the BBC's Africa documentary, broadcast last week, veteran nature presenter Sir David Attenborough said that "some parts of the continent have become 3.5 degrees Celsius hotter in the past 20 years".

This prompted a fair bit of discussion, and rightly so - the BBC has since called the statement "disputable" and removed it from repeats of the programme. But if the BBC got it wrong, what could it have said? Here we look through the scientific literature to find some material the BBC could have used instead.

The issue came to light with a flurry of inquisitive Twitter users expressing surprise at the 3.5 degree claim shortly after  the programme aired last Wednesday. The Guardian's  Leo Hickmantook a closer look with a blog post headlined 'BBC exaggerated climate change in David Attenborough's Africa' - and the story was widely picked up in other papers. The  Times, the Telegraph and the  Daily Mail all covered the story yesterday - the latter calling the episode "an embarrassing climbdown over climate change claims".

The BBC swiftly removed the offending phrase from Sunday's repeat, with the admission that Attenborough's words "should have been more carefully scripted". All that remains in the programme as broadcast is a rather vague statement that "Africa's climate is certainly changing".

First hurdle

Looking for temperature trends across Africa is not like looking for trends in the UK or elsewhere in the Northern Hemisphere. Temperature measurements are only  quite patchyacross the continent, and where measurements do exist they don't extend very far back in time.

With temperature data only available for relatively short periods of time, it's harder to spot long term changes - or trends. And gaps in the geographical coverage make it hard to see how widespread any detected trends are.

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The results of a new study on the effect of earthworms on greenhouse gas emissions attracted a fair bit of attention last week. Here, the researchers respond to a few of the most popular comments and misconceptions about their findings.

Last week, our study on the effect of earthworms on soil greenhouse emissions appeared in Nature Climate Change. Although we were pleased about all the attention focused on our work in  Carbon Brief and the  Guardian, almost inevitably some misunderstandings showed up in online discussions. Here are our answers to six of the most frequently posted comments and questions:

1: Earthworms cause global warming, not humans, so we can all stop worrying now

This comment, which also comes in another form - that we're making excuses for human-caused global warming - is without a doubt the most serious misunderstanding of our work.

Humans cause global warming, not earthworms. Since earthworms have been around for hundreds of millions of years, it would be naïve to assume they suddenly started to cause global change somewhere in the previous century.

In the case of carbon dioxide, the largest cause of increasing atmospheric concentrations is burning fossil fuels and land-use change. Whereas with nitrous oxide, the largest cause is the enormous amount of nitrogen fertilizer that mankind applies to agricultural soils.

Our study shows earthworms are an important actor through which humans can cause nitrous oxide emissions. It also suggests that, due to the increasing habitat for earthworms over the coming decades, earthworm-induced emissions may increase. But these emissions are largely conditional on humans adding fertilizer to agricultural systems.

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Science writers are constantly on the hunt for analogies to help readers situate climate phenomena on their mental map. But nothing beats seeing something for yourself. And that's what Chasing Ice - which is still out in cinemas - is designed to do. With very beautiful footage, it makes subject matter that's dry on paper compelling.

Melting glaciers are one of the tangible areas where scientists can see the effects of a warming climate. But reading reports giving constantly-revised estimates about whether glaciers around the world are retreating by a few feet more or less a year loses a bit of impact in the telling. Even though we use trusty measurements like the length of a football field or the height of a building as a marker, it's really hard to picture. 

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Beth Rudge

New  research from universities in the US, Australia and the UK has tested how different pictures make people feel about whether climate change is important, and whether they can do something about it.

Inspired, we have decided to conduct our own experiment on you, dear readers.

Researchers showed people images used to illustrate newspaper climate change stories. They mostly split into three categories: pictures of climate impacts, energy futures - meaning new energy sources like solar panels, and pictures of celebrities and politicians. 

Images of climate impacts made people feel like climate change is important, but they also made them feel like there's not much they can do to stop it.

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The new year has brought redundancies in the mainstream media as organisations attempt to cut costs. How can specialist climate coverage escape being confined to the blogosphere when news organisations are losing money and journalists are busier than ever? Carbon Brief talks to two online organisations that aim to bridge the divide between special interest and mainstream news on climate change. 

It's only mid-January, but two huge media outlets have already announced job cuts. In an email to employees, the editor of the Financial Times, Lionel Barber,  announced the newspaper - one of the few remaining still to make a profit - will cut staff numbers through voluntary redundancies and focus on its digital offering. News agency Reuters, too, is shrinking. According to media blog  The Baron, it admitted last week that the 60,000-strong company has announced redundancies. 

In this environment, it's clear that climate change journalism in the mainstream media is under pressure. For one, the  New York Times announced it has dismantled its nine-strong environment desk. This leaves the Los Angeles Times  the only one of the US's top five newspapers by readership left with a designated environment desk. And last year, BBC environment correspondent  Richard Black left the BBC amidst wider job cuts at the corporation.  

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Mayor of London Boris Johnson bemused the world in the run up to the Olympics with a patriotic  speech about table tennis's purported ancestor 'whiff-whaff', an ancient game built around the idea of a good back and forth. 

Johnson's conception of climate science also seems to be based around the idea of a good back and forth - between scientists and skeptics. He gave his latest thoughts on the subject for   Telegraph readers today, as from his window in snowy Islington, he muses on the subject of snowy winters. He turns to the theories of climate skeptic meteorologist, Piers Corbyn, who believes that far from warming, the globe might be heading for a "mini ice age".

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