Global warming is intensifying El Niño weather

https://www.theguardian.com/environment/climate-consensus-97-per-cent/2018/aug/29/global-warming-is-intensifying-el-nino-weather

John Abraham

Wed 29 Aug 2018 06.00 EDT
Last modified on Wed 29 Aug 2018 07.00 EDT

As humans put more and more heat-trapping gases into the atmosphere, the Earth warms. And the warming is causing changes that might surprise us. Not only is the warming causing long-term trends in heat, sea level rise, ice loss, etc.; it’s also making our weather more variable. It’s making otherwise natural cycles of weather more powerful.

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El Niño cycles have been known for a long time. Their influence around the world has also been known for almost 100 years. It was in the 1920s that the impact of El Niño on places as far away as the Indian Ocean were identified. Having observed the effects of El Niño for a century, scientists had the perspective to understand something might be changing.

For example, in 2009–2010, intense drought and heat waves gripped the Amazon region – far greater than expected based on the moderate El Niño at the time. In addition, from 2010 to 2011, severe drought and heat waves hit the southern USA, coinciding with a La Niña event. Other extreme weather in the US, Australia, Central and Southern America, and Asia stronger than would be expected from El Niño’s historical behavior have raised concerns that our El Niño weather may be becoming “supercharged.”

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It means if you live in an area that is affected by an El Niño or La Niña, the effect is likely becoming magnified by climate change. For instance, consider California. There, El Niño brings cool temperatures with rains; La Niña brings heat and dry weather. Future El Niños will make flooding more likely while future La Niñas will bring more drought and intensified wildfire seasons.

Unsurprisingly, we’re already seeing these effects, with record wildfires in California fueled by hot and dry weather. We are now emerging from a weak La Niña, so we would expect only a modest increase in heat and dryness in California. But the supercharging of the La Niña connection is likely making things worse. We would have California wildfires without human-caused global warming, but they wouldn’t be this bad.

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