It seems that never a season goes by without recording some weather extreme or other. The warmth we’ve experienced this year means that 2020 is set to be another record, but without the driver of an El Nino.
In other words, it’s rising levels of greenhouse gases that are driving the 2020 temperatures. Professor Adam Scaife is the Met Office head of long-range prediction. He said: “Natural events – such as El Niño-induced warming in the Pacific – influence the climate system, but in the absence of El Niño, this forecast gives a clear picture of the strongest factor causing temperatures to rise: greenhouse gas emissions.”
The writing is on the wall for the long term climate trends, make of it what you will, but it is also still the case that overarching climate phenomena like El Nino (also called ENSO – El Nino Southern Oscillation) are also a major influence local weather conditions we experience on the ground. Global warming goes alongside freezing winters – one does not disprove the other.
El Nino is probably the most familiar climate event to most of us, especially since it hit the headlines in 2015 when forecasters told us to brace ourselves for a Super El Nino. Concerned about the humanitarian impact of this, the government commissioned a global impact report from the University of Reading’s Department of Meteorology. In other studies, that Super El Nino was shown to be responsible for outbreaks of disease around the world. In the UK it gave us an exceptionally warm December with rainfall and flooding across the north.
El Niño El Nino, the unusual warming of sea-surface Pacific waters off the South American coast, is a naturally occurring event, occurring every five to seven years on average, and varying in strength, although evidence is emerging that climate change will increase the odds of a strong El Niño taking place
In an El Nino year, we experience more extreme weather conditions as the warmer or cooler than normal ocean temperatures can affect weather patterns around the world by influencing high and low pressure systems, rainfall and winds – and that includes the powerful jet stream.
To see how El Nino drives or climate, check out this animation from the UK Met office.
El Nino may have grabbed the headlines, but there are other oscillations, as they are known, that weathermen watch carefully, and they all interact. The Arctic Oscillation (AO) determines how far south cold winds come, and how strong they are. The Madden-Julian Oscillation (MJO) is an eastward moving ‘pulse’ of cloud and rainfall near the equator that typically recurs every 30 to 60 days.
The effects of these overarching climate oscillations on pressure systems (highs and lows) influence the weather we experience.
The Beast and the Pest
The Beast form the East is a familiar visitor to our shores now and was particularly fierce last Winter. When atmospheric conditions favour it, it swirls in bringing freezing air from Siberia and temperatures struggle to get above zero. The Pest from the West brings warmer, wetter air from the south west and that signals heavy rain. If its thunderstorms come hard on the heels of a cold snap and before the thaw, the risk of flooding is only greater.
The signs are that the weather gods have not been brewing a big El Nino event for us this year, but forecaster rarely look beyond 30 days and, one way of another, winter is coming.
As the saying goes, fix the roof while the sun is shining – now’s the time to give your building a health check. You might want to re-read your insurance policy and make sure you have good storm damage cover. Do remember, though, that any claim can be affected if the building is found to have been poorly maintained in the first place.
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