Extremes become the norm - is this ‘global weirding’?

Is ‘global weirding’ a better explanation than climate change for our extreme weather?

Colder winters, drier summers – and even the opposites – are occurring more frequently and growing in intensity. Trends suggest that this long term change is due to greenhouse gases steadily building up in the atmosphere, but is it just this that is causing extremes in our weather to become more normal?

Some people are beginning to blame ‘global weirding’ for our extreme weather. I’d never heard the term until BBC’s Horizon dedicated a whole programme to it, but the term was coined by Rocky Mountain Institute co-founder Hunter Lovins and popularised by New York Times op-ed columnist Tom Friedman in 2010.  It primarily concerns climate extremes, says Auroop Ganguly, an expert in climate change and severe weather conditions from Northeastern University.

“In certain situations, these need to be defined in terms of their impact on natural, engineered and human ecosystems,” he said. “Global warming, which addresses changes in average global temperatures, does not begin to convey the range of severe weather-related events and changes in weather patterns that can occur as a consequence of climate change.”

Climate change refers to a long-term trend in the average global temperature, while global weirding applies to fluctuations seen on a shorter scale – the colder winters, the drier droughts, and the more unpredictable storms.

"I think that global 'weirding' is the best way to describe what we're seeing. We are used to certain conditions and there's a lot going on these days that is not what we're used to, that is outside our current frame of reference," says climate scientist Katharine Hayhoe of Texas Tech University.

Floods and droughts are usually down to the El Niño and El Niña effect – naturally occurring but poorly understood events which follow the heating and cooling of the Pacific Ocean near the equator. However, their effects are being exacerbated by the background of a warming world. Although climate change is never explicitly blamed, the events are consistent with what is expected of climate change.

Ganguly says his research on heat waves suggests that while they will continue to be geographically varied, the rising trend in the projected intensity, frequency and duration of heat waves ‘are unmistakable’. It also suggests cold snaps will continue to the end of the century – even though the overall trend is one of warming.

But what if some of these events happen every X number of years? We know that the planet cycles between warmer and cooler periods, so what if some of the extremes we’re experiencing now are just weather patterns that we’re ‘due’?

Take for instance the ‘once-in-a-100-years’ drought which occurred in China last year. The name implies that it’s something that the country has experienced before and is likely to experience again. The drought dried up hundreds of reservoirs and rivers and evaporated drinking water supplies. This led to a government rain making operation – they fired thousands of rockets to seed clouds with silver iodide and other chemicals. It may have worked – the heavens opened and there was a record 30cm of rain in some places in just 24 hours.

Perhaps something to bear in mind as the global community seek to mitigate some of the effects of anthropogenic global warming.