January 5, 2016

expert reaction to Met Office data on December’s record-breaking rainfall and temperatures

The Met Office has released provisional figures for rainfall in December 2015, and they report that the month was the wettest and warmest December on record, as well as the wettest calendar month.

Prof. Corinne Le Quéré, Director of the Tyndall Centre, University of East Anglia, said:

“Increases in heavy rainfall are an anticipated consequence of a warming climate, and that’s raising the risks of floods.  Increases in heavy rainfall have been observed over most of Europe and North America already.  We shouldn’t be surprised by a warmer climate with more intense rainfall in the UK.

“We can limit future flood risks by acting rapidly to tackle climate change, and that means reducing fossil fuel emissions to near zero and using renewable energy and more efficient technology instead.”

Dr Chris Huntingford, from the Centre for Ecology and Hydrology, said:

“No single year of extremes can be used as direct evidence of human influence on weather, but with more statistics such as these emerging worldwide, this suggests we are not just witnessing natural climate fluctuations.

“More intense rainfall combined with warmer temperatures are in keeping with many models of the physics of atmospheres, designed to estimate the impact of higher levels of atmospheric greenhouse gases. However researchers will not be congratulating themselves on any computer model accuracy, because there remains significant challenges ahead. The average predictions of climate change computer simulations may be correct, but the emphasis now is to understand at very fine regional level, precisely what variation might be expected. The Met Office, the UK research laboratories and universities are working towards this, because ultimately planning needs much more than generalities. We need to know at almost backyard scale expected future storm and rainfall pattern changes, to aid local resilience planning.”

Prof. Richard Allan, Professor of Climate Science at the University of Reading, said:

“The remarkably warm and wet conditions of December 2015 across the UK resulted from unusual weather patterns globally, supercharged by the warming of climate that has taken place due to human activities.

“An unusually persistent air flow from the south led to mild conditions across Europe and the continual supply of moisture laden air with resulting heavy rainfall over northern Britain.  Unusual ocean temperatures including east Pacific El Nino warmth and a surprising cold blob of ocean temperatures in the North Atlantic both played a role, influencing the formation and track of storms dished up by the jet stream (fast moving air high up in the atmosphere, governed by the rapid drop in temperature from the warm sub-tropics to the cold Arctic and responsible for steering storms toward or away from the UK).

“However, the fickle nature of weather patterns is also master of ceremonies. When scientists run thousands of computer simulations starting from the same unusual pattern of ocean temperatures this can make certain weather patterns more likely but a multitude of story-lines are possible.

“What is certain is that a warming climate is causing heavy rainfall events and associated flooding to become more severe. While the timing and location of extreme events are determined by weather patterns, as the climate warms the greater quantities of moisture in the air further fuels the intensity of rainfall when and where these deluges occur.

“Continuing intensification of heavy rainfall events is one of the most certain consequences of climate change during this century.”

Prof. Meric Srokosz from the National Oceanography Centre, Southampton, said:

“It is unsurprising that the UK is experiencing a warmer wetter winter, as this is what you would expect (and models predict) as the atmosphere warms and can hold more moisture.  The effect is probably exacerbated by the strong El Niño currently occurring in the tropical Pacific which affects global weather patterns.”

Prof. Myles Allen, Professor of Geosystem Science at the University of Oxford, said:

“The Intergovernmental Panel on Climate Change predicted back in 1990 that precipitation would increase in mid-latitudes in winter, and that winters would warm faster than the global average; and even, tentatively, that precipitation would become more concentrated into intense short-duration events.  Since then, the world has warmed by getting on for half a degree, and we are starting to see these impacts emerge.

“So none of this should really come as a surprise to anyone, and the (hopefully diminishing) band of diehards who continue to dismiss climate change concerns as just ‘green crap’ have mud on their hands this New Year.”

Prof. Piers Forster, Professor of Climate Change at the University of Leeds, said:

“The record breaking wet and warm December is not just due to climate change but I am sure that manmade climate change played a significant role.

“Warmer, wetter winters with increases in extreme rainfall are entirely expected and predicted responses to climate change. Physics tells us that the 4.1C warmer December would bring 30% heavier extremes of 24 hour rainfall rates, and this is what we saw across much of the north of the UK.”

Prof. David Reay, Professor of Carbon Management at the University of Edinburgh, said:

“Temperature and rainfall records will inevitably tumble as climate change intensifies.  For the UK a pattern of warmer, wetter winters and drier, hotter summers is common to almost all climate projections.

“More important than these shifting averages though are the changing extremes. It is the increasingly extreme rainfall events, storm surges, heatwaves and droughts that will truly test our resilience to climate change. On the evidence of the past month we are far from prepared.”

* http://www.metoffice.gov.uk/news/releases/archive/2016/december-records

Declared interests

None declared