The "pause" in warming myth: debunked

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The Australian newspaper continues to publish stories and editorial pieces on the so-called "pause" in warming. The Australian Press Council has previously expressed “considerable concern” about inaccurate climate change coverage in the Australian.

Here are some handy myth-busting responses to this misinformation.

Myth One: There has been a pause in global warming

Nope, the Earth continues to warm strongly. NASA, NOAA, the IPCC and a long list of other trusted organisations have confirmed that yearly global average temperature continues to climb. 2013 marked the 37th year in a row that the yearly global temperature was hotter than average. 13 of the hottest 14 years have occurred this century.

Source: interactive NOAA graph

The Earth continues to warm strongly which is why we keep seeing long standing temperature records broken. 2013 was the hottest year on record in Australia.

Therefore it is misleading to say that there has been a "pause" in global warming.

What fuels the myth that global warming has "paused" is that the rate of air temperature rise does fluctuate in the short term. In recent years the rate of air temperature rise has been slower. This is not unusual in the longer-term temperature record. Sometimes air temperature rises quickly and sometimes more slowly. It is crucial that we look at the long-term trend. The long-term trend is that temperature is rising. Each calendar year will not necessarily be warmer than the year before. But with the current level of greenhouse gas emissions, scientists expect each decade to be warmer than the previous one.

The other aspect is that when most people think about climate change they only think about rising air temperatures. In fact the excess heat trapped by greenhouse gases warms the air, the ocean, the Earth’s land surfaces, and melts ice and glaciers. The ocean is the big ticket item as 93% of the warming since 1955 has been absorbed by the world's oceans. In fact, the oceans have warmed strongly since 1998 - the year that the so-called "pause" began.

Those seeking to mislead the public seek to cherry pick one part of the Earth’s system and short periods of time to imply that global warming has paused. Unfortunately media articles often state that there is a pause in warming, rather than referring to the fluctuation in the rate of air temperature rise. The reality is that the Earth continues to warm strongly with grave implications for humanity.

Myth Two: the earth’s climate is not as sensitive to CO2 emissions as originally thought

In a nutshell:

No, there has been no significant change in the estimates of climate sensitivity by the Intergovernmental Panel on Climate Change (IPCC), the world’s peak body on climate change science.

The Earth is highly sensitive to rising CO2. We’ve already passed a landmark 400 parts per million and the global average temperature has already risen by 0.8°C since 1880. Two-thirds of this warming has occurred since 1975. This is having serious impacts already. Mass from glaciers and ice sheets is being lost, sea level is rising and a warming climate is increasing the frequency and severity of many extreme weather events and is changing rainfall patterns, creating risks for human wellbeing, the economy and the environment.

Climate scientists have been warning us for decades of the grave dangers of a changing climate and the imperative to act. The latest IPCC report has warned us unequivocally yet again.

More detail:

Climate sensitivity is a pretty complex scientific concept that is often deliberately misinterpreted, so bare with us as we break it down.

Equilibrium Climate Sensitivity (ECS) is an estimate of the amount of temperature rise that would result from a doubling of CO2 concentration in the atmosphere after the climate system has reached a new equilibrium state. The higher the climate sensitivity the more warming we’re likely to see. Our climate is very sensitive to increases in CO2 with the IPCC projecting that ECS is between 1.5°C and 4.5°C. All of the possible temperatures within this range have scary implications. Even if our planet only warms by 1.5°C this will have disastrous consequences. For example many Island States, such as Maldives, may become completely uninhabitable due to rising sea levels.

The IPCC uses three models to measure climate sensitivity and in their latest report the climate sensitivity of one of these models was readjusted from a range of 2° C - 4.5°C to 1.5°-4.5°C. The IPCC AR5 does not give an estimate to which value within the ECS range is most likely. Thus claims that the IPCC has “downgraded” earlier estimates of climate sensitivity are not correct. It is also important to remember that a reduction of 0.5°C at the lower end of the model is not a game-changer anyway. There will still be devastating consequences if our world warms by 1.5°C.

Check out our unpacking of the IPCC report here.