Probing the deep: An in-depth look at the oceans, climate change and the hiatus

  • 20 Oct 2014, 08:40
  • Roz Pidcock and Rosamund Pearce

Oceans cover more of the planet than anything else. So it makes sense that we need to know what's happening to them to understand how humans are changing the climate. 

If you follow climate science, you'd be forgiven for being a little confused recently by different news reports suggesting the oceans are warming, slightly  cooling or doing  nothing at all.

So are the oceans hotting up or aren't they? And how does what happens beneath the waves influence what we feel up here on earth's surface? Here's our top to bottom look at the oceans and climate change.

More heat in, less heat out

Scientists have known for centuries that greenhouse gases in the atmosphere, such as carbon dioxide and methane, trap heat and warm the planet. This is known as the greenhouse effect.

Scientists use satellite measurements to monitor how much of the sun's energy enters earth's atmosphere. A different set of measurements tells them how much finds its way out again.

The difference between those numbers is increasing, which means the earth is  trapping more heat than it used to. And that means the planet  must be warming.

A hiatus in surface warming

An interesting question is why temperatures at earth's surface - that's the air above land and the very top of the ocean - don't always reflect what's happening to the planet as a whole.

Over the last 15 years or so, surface temperatures have risen  much slower than in previous decades, even though we're emitting greenhouse gases  faster than we were before.

This is what's become known as the "hiatus", "slowdown" or even "pause" in surface warming.

This raises an obvious question. If earth is  gaining heat but the surface isn't warming very much, where is the heat going instead?

Where does the heat go?

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How we can make good decisions about geoengineering

  • 30 Sep 2014, 15:15
  • Dr Rob Bellamy

Next month's synthesis report from the Intergovernmental Panel on Climate Change (IPCC) is due to give the organisation's verdict on geoengineering, a radical set of proposals to use large-scale technologies to tackle climate change.

There are two types of geoengineering. Carbon geoengineering seeks to remove carbon dioxide from the atmosphere, for example by capturing it from the air and storing it underground, or by adding iron to the oceans to trigger carbon-absorbing algal blooms.

Solar geoengineering is different. It seeks to reflect some sunlight away from the Earth before it can be trapped by greenhouse gases.This can be done, for example, by spraying clouds with sea salt to make them more reflective, or by stratospheric aerosol injection, where reflective particles are pumped into the atmosphere.

Geoengineering

My colleagues and I have been  examining the importance of 'opening up' discussion about geoengineering to alternative options, different perspectives and real world complexity.

'Closing down' assessment

Our earlier research has shown that the ways in which researchers frame assessments of geoengineering have important effects on the conclusions people come to.

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How TV news covered the Intergovernmental Panel on Climate Change’s three big reports

  • 23 Sep 2014, 00:01
  • Mat Hope

TV audiences around the world aren't hearing much about climate science.

That's the main conclusion of a new study looking at how TV news covered the Intergovernmental Panel on Climate Change's (IPCC) three big reports earlier this year.

While the IPCC's reports made a  small splash in the print media, the same wasn't true of television news. Media in many countries barely covered the reports. And when they did, they used an old-fashioned "doom" narrative to explain them, research by Oxford University's Reuters Institute finds.

That's concerning, because many people still get their news from the TV, and place particular trust in TV news to deliver a balanced account of climate science.

Here's which channels covered the reports, how, and why it matters.

Country divergence

The IPCC's first report on the science behind climate change was launched in October 2013. A second report on the impacts of climate change was released the final day of March 2014, with a  third report looking at policies to cut emissions following a couple of weeks later.

The Reuters Institute looked at how a selection of news bulletins in the UK, China, India, Brazil, Australia and Germany covered all three reports on their launch day, and the day before.

13 out of the 36 main news bulletins the Reuters Institute studied covered the IPCC reports. That adds-up to about 34 minutes of airtime.

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