Why isn’t it getting colder?

Most people in New Zealand and Australia will be familiar with the terms El Niño and La Niña which describe the Pacific ocean-atmosphere oscillation and which influence local temperature and rainfall. For Australia, El Niño events tend to bring warmer temperatures and drought while La Niña often brings widespread rain and flooding. The floods of 1973-1974 occurred during a La Niña. La Niña events also tend to bring cooler temperatures. This oscillation between El Niño and La Niña creates natural variations in temperature from warmer El Niños to cooler La Niñas. This cycle does not cause long-term changes in temperature however as over time, the two tend to cancel each other out.

This cycle of El Niño/La Niña causes shifts in the temperature of the equatorial Pacific Ocean which lasts for decades or more. This is known as the Pacific Decadal Oscillation. Since 1998, the oscillation has been in a cooling phase so it should have been getting colder. Yet we know that the temperature over the last decade has actually increased by about 0.05°C. A paper published in Nature this month finds that this La Niña-like decadal cooling has actually lowered global temperatures by about 0.15°C for the last decade. This has cancelled out much of the warming due to human-made greenhouse gases. In an article published in The Conversation, the authors of this paper write,

When the climate cycle that governs that ocean cooling reverses and begins warming again, the planet-wide march toward higher temperatures will resume with vigor.

So the question should not be, has global warming stopped?, but rather, why isn’t it getting colder? The answer is because natural variation caused by the Pacific Decadal Oscillation is currently masking global warming which is still happening at a rate which is unprecedented in at least the last 11,300 years.

There’s a good post at the blog Open Mind which explains this better than me called, El Niño and the Non-Spherical Cow. A cut and paste from their post:

The bottom line is that those who claim that global warming has “stopped” or even “paused” are deluding themselves. The phrase “global warming” refers to climate change, including temperature increase, which is caused by mankind, and that has continued unabated. In fact, if it weren’t for the continued warming due to human activity, natural variations (like ENSO) would have brought about a notable cooling over the last decade or so. But earth hasn’t cooled during that period, not even at the surface where we notice it most immediately, and that’s because the man-made component — global warming — has continued.

Wattsupwiththatblog also addresses this paper in a good post titled, Judith Curry is blown away?. A cut and paste from their post:

Global warming is a consequence of rising atmospheric greenhouse gas concentrations that act to trap outgoing long-wavelength radiation and increase the amount of energy in the climate system. This energy is then distributed across the climate system, with the majority (90% or more) going into the oceans. How this energy is distributed across the climate system will, however, depend on the properties of the different parts of the system. It seems reasonable that there will be times when a larger fraction goes into the oceans and other times when this fraction reduces, increasing the fraction heating the surface and atmosphere.

No-one knows when the oscillation will swing back to a warming phase but should we be thinking about spraying the planet with sunscreen before this happens? Am I the only one who thinks we need to do something drastic before all of the ice melts?

17 Replies to “Why isn’t it getting colder?”

  1. You are not the only one at all Rachel. I do what little one person can do. The way I see it especially in the US is it is going to take the government to get involved. Our government right now is so divided they cant get squat done. Not to mention half of the republican side still doesn’t even believe in global warming. Others countries have done a lot but ours is just plain stuck on this and many issues.

    1. My own country, Australia, has also done diddly squat and seems to be quite divided as well. I saw a cartoon recently which summed it all up rather well –

      1. And to think the people of Australia were assured by Professor Ross Garnaut that world leaders were moving to an international agreement to control carbon emissions by 2015 effective from 2020! Have we been misled by our Labor government and Garnaut who is remarkably low profile this election?

      2. Tony Abbott wasn’t in government, making changes that affected our lives, when he made those statements, Rachel. The policies of Labor and Ross Garnaut have had far reaching effects on the Australian people and industry.

      3. I’m not familiar with whatever changes the present Labour government made regarding climate change but I do know they haven’t been nearly significant enough and so some criticism is certainly deserved. However, they have not gone so far as Abbott has with his anti-science sentiment and outright denial of climate change. And now his about-face, with no explanation whatsoever, no apology or acknowledgement that he was wrong and his intention to do even less than Labour is worse in my view. As George Monbiot puts it,

        Labor’s failure to protect the natural world ensures that Abbott’s philistinism is harder to contest.

        I wholeheartedly agree with him.


  2. Unfortunately, we have already locked in huge climate changes by reaching 400m ppm. The only choices left for us now are whether we want to be totally ice free, or merely mostly ice free, over the next few hundred years.

    1. Yes, I’ve been thinking recently about how hard it might be to re-freeze the ice. Probably VERY.

      1. Certainly wildly beyond our current and foreseeable technology. The alternative would be a vast reinjection of CO2 back into the ground at a rate much faster than we liberated it — probably equally impossible.

        Unfortunately, at this point I think humanity is going to have to try and survive with the hand it has dealt itself. Not a pretty forecast, for sure.

      2. That’s a very cute squirrel, Rachel!

      3. I saw a program recently about the red squirrel which is native to the UK and being wiped out by the introduced grey squirrel. So in solidarity with the squirrel’s plight, I changed my avatar. I also got sick of looking at my face.

  3. In geopolitical terms, the biggest effect on human society may be that due to sea level rise. You can see on this map, http://geology.com/sea-level-rise/, the effect of rise of even one metre on big river deltas such as the Nile. Rich countries can probably afford to take defensive measures – relocate New Orleans, build a sea wall round Manhattan and the like – but less affluent nations such as Egypt and Bangladesh as well as coral island states are likely to experience mass migrations of climate refugees.

    Exacerbating this will be changes in rainfall patterns and water shortages. Already there is tension amongst the nations dependent on river flow from the Himalayas for the bulk of their fresh water. Outbreaks of water wars are not inconceivable.

    The 22nd century should bring very interesting times.

    1. Don’t underestimate the impact of heat either. Humans cannot survive a wet bulb temperature of >35C (100% humidity) for extended periods of time.

      “A sustained wet-bulb temperature exceeding 35 °C is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan; at this temperature we switch from cooling the skin (losing heat to the environment), to warming it.”

      At present, no-where on Earth produces web bulb temperatures as high as this, but there is evidence that during hot-house periods in Earth’s past, they did get this high. http://www.purdue.edu/newsroom/research/2010/100504HuberLimits.html

  4. I’d really like to see the data for the rest of the last 1,000,000,000 years before making any predictions. Decades of data, and even 11,300 years of data, just seem like incredibly short time scales to me.

    1. It’s not just about data though. The evidence that we are undergoing human-induced global warming is incredibly strong. We understand how CO2 and other greenhouse gases influence the outgoing radiation. We have direct satellite measurements of this effect. We have measurements of how the ocean heat content is rising. We can measure the change in pH in the oceans due to increased CO2. There are some uncertainties as to precisely the effect of the continued increase in energy in the climate system, but some aspects are quite certain. Sea levels will rise (maybe 0.5m or more by 2100). The Arctic will be ice free in summer within the next decade (probably). If melting in Greenland were to accelerate, sea level rises could be quite severe. More energy also means higher temperatures and more heat waves.

      So, there are some uncertainties but the risks associated with anthropogenic global warming are so high that doing nothing and waiting is, in my view, an incredibly foolish strategy and one that – if we do follow it – we will regret in the years to come.

      1. I agree, that it would be very foolish to adopt a ‘wait and see’ approach to global warming. Apart from mitigating global warming, there are many other good reasons to shift from fossil fuels to carbon-free energy sources and China is starting to realise this. From the NYTimes:

        The grimy haze blanketing Beijing and other Chinese cities comes from motor vehicles, factories, power plants and furnaces that also emit carbon dioxide, the main global warming gas from human activities. The widespread ire about air pollution has forced China’s new leadership to vow firmer, faster measures for cleaner air that are likely to reduce carbon dioxide output, especially from coal, experts said. “The public concern about the air pollution has helped raise awareness about broader environmental problems,” said Mr. Jiang, a researcher at the Energy Research Institute, which advises the Chinese government. “This will be a big help in pushing China.”

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