Climate Change Runs With Variations

Give someone a cold spell or extra rain and they’ll think climate change and global warming has ended. If only we could give them a little bit of common sense as well, we might be able to make some progress in helping people see that overall trends are separate and distinct from what happened last night.

Barrie Hunt, an Honorary Research Fellow with CSIRO Marine and Atmospheric Research, has published results from climatic model simulations which show that short-term cooling in global temperatures do not equal an end to global warming.

“Despite 2010 being a very warm year globally, the severity of the 2009-2010 northern winter and a wetter and cooler Australia in 2010 relative to the past few years have been misinterpreted by some to imply that climate change is not occurring,” said Hunt.

“Recent wet conditions in eastern Australia mainly reflect short-term climate variability and weather events, not longer-term climate change trends. Conclusions that climate is not changing are based on a misunderstanding of the roles of climatic change caused by increasing greenhouse gases and “climatic variability due to natural processes in the climatic system.

“These two components of the climate system interact continuously, sometimes enhancing and sometimes counteracting one another to either exacerbate or moderate climate extremes.”

Not only did Hunt find that natural temperature variations could and can last for some 10 to 15 years, but that even 50 years into the future we will be experiencing cold snaps in the northern hemisphere that defy logic, with temperatures 10°C to 15°C below the average.

“These results suggest that a few severe winters in the Northern hemisphere are not sufficient to indicate that climatic change has ceased. The long-term trends that characterise climate change can be interpreted only by analysing many years of observations.”

“Future changes in global temperature as the concentration of greenhouse gases increases will not show a simple year-on-year increase but will vary around a background of long-term warming. Winters as cold as that recently experienced in the Northern Hemisphere, however, will become progressively less frequent as the greenhouse effect eventually dominates,” Mr Hunt said.

Source: CSIRO

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