Tuesday, February 27, 2018

Freak WARMING in the Arctic is to blame for the big chill over Europe: Experts warn it's 'never been this extreme' and predict it may happen more often due to climate change

On the northern tip of Greenland, the Cape Morris Jesup meteorological site has had a record-smashing 61 hours of temperatures above freezing so far in 2018 (bottom inset), linked to a rare retreat of sea ice in the Arctic winter darkness. 'It's never been this extreme,' said Ruth Mottram, a climate scientist at the Danish Meteorological Institute. Around the entire Arctic region, temperatures are now about 20C (36°F) above normal (main), at minus eight degrees Celsius (17.6°F), according to DMI calculations. The freak warming around is sending a blast of Arctic cold over Europe in a sign of 'wacky' weather (top inset) that may happen more often with man-made global warming.

The freak warming around is sending a blast of Arctic cold over Europe
It is a sign of 'wacky' weather that may happen more often, scientists claim
One area has had a record-smashing 61 hours of temperatures above freezing

Europe has been buffeted by freezing temperatures in recent days and experts say this is the result of freak warming in the Arctic.

The Arctic is experiencing one of its hottest winters on record, with temperatures at the North Pole surging above freezing.

These unusual conditions, which scientists say have 'never been this extreme', are causing a disruption to the Arctic polar jet stream.

The jet stream carries winds east to west across the planet, at speeds of up to 200mph (320kph), in the upper atmosphere.

Warmer air in the Arctic has sent them off their usual course, blasting cold air over Europe - something likely to happen more often thanks to man-made global warming, researchers say.

The North Pole has surged above freezing despite it being the dead of winter, stunning scientists. This graphic shows global forecast system data of temperature difference from normal (in °C) on Sunday over the Arctic

On the northern tip of Greenland, the Cape Morris Jesup meteorological site has had a record-smashing 61 hours of temperatures above freezing so far in 2018.

This is linked to a rare retreat of sea ice in the Arctic winter darkness.

'It's never been this extreme,' said Ruth Mottram, a climate scientist at the Danish Meteorological Institute (DMI).

Warmth was coming into the Arctic both up from the Atlantic and through the Bering Strait, driving cold air south.

Around the entire Arctic region, temperatures are now about 20°C (36°F) above normal, at -8°C (17.6°F), according to DMI calculations.

The Arctic is experiencing one of its hottest winters on record, with temperatures at the North Pole surging above freezing. This graphic shows declining sea ice concentrations since February 20, 2018

HOW DO RISING TEMPERATURES IN THE ARCTIC CREATE COLD WEATHER IN EUROPE?

As long ago as 1973, a study suggested that an ice-free Arctic Ocean could make regions further south colder.

That 'warm Arctic, cold continent' (WACC) pattern is sometimes dubbed 'wacc-y' or 'wacky' among climate scientists.

When unusually warm air enters the region, it melts ice covering the waters of the Arctic Ocean.

This ice normally serves as an insulator, stopping the flow of thermal energy from the water’s surface into the atmosphere.

Without the ice in place, the oceans can transfer a huge amount of this energy into the air above.

This in turn increases air temperatures and this warm air rises up into the upper atmosphere, where it reaches the jet stream.

Jet streams are fast flowing, narrow currents of air that carry warm and cold air across the planet, much like the currents of a river.

They cover thousands of miles as they meander near the tropopause layer of our atmosphere.

The strongest jet streams are the polar jets, found 30,000 to 39,000 ft (5.7 to 7.4 miles/ 9 to 12 km) above sea level at the north and south pole.

In the case of the Arctic polar jet this fast moving band of air sits between the cold Arctic air to the north and the warm, tropical air to the south.

When uneven masses of hot and cold meet, the resulting pressure difference causes winds to form.

During winter, the jet stream tends to be at its strongest because of the marked temperature contrast between the warm and cold air.

The bigger the temperature difference between the Arctic and tropical air mass, the stronger the winds of the jet stream become.

The Arctic polar jet, which can reach speeds of up 200mph (320kph), flows over the middle to northern latitudes of North America, Europe, and Asia and their intervening oceans.

It moves from East to West, although its exact route varies and can be affected by various factors.

With the ice melt in the Arctic and the introduction of warmer air, the route of the jet stream becomes wavier and more erratic.

That means that the colder air it carries from the Arctic can penetrate further south and warmer airs from the tropics is carried further north.

If the jet stream’s meander buckles south of the UK, it attracts cold air from the Arctic.

Conversely when it swings north, it sucks warm air from the tropics.

To the south, a rare snow storm hit Rome on Monday and some Brussels mayors planned to detain homeless overnight if they refused shelter with temperatures set to fall as low as -10°C (14°F) in the coming week.

Hit by easterly winds from Siberia, cities from Warsaw to Oslo were colder than -8°C.

As long ago as 1973, a study suggested that an ice-free Arctic Ocean could make regions further south colder.

That 'warm Arctic, cold continent' (WACC) pattern is sometimes dubbed 'wacc-y' or 'wacky' among climate scientists.

'Wacky weather continues with scary strength and persistence,' tweeted Professor Lars Kaleschke, a professor at the University of Hamburg.

The Cape Morris Jesup meteorological site has had a record-smashing 61 hours of temperatures above freezing so far in 2018. This graphic shows global forecast system data of temperatures (in °C) on Sunday over the Arctic

Warmth was coming into the Arctic both up from the Atlantic and through the Bering Strait, driving cold air south. This is linked to a rare retreat of sea ice in the Arctic winter darkness. This image shows the current extent of sea ice in the Arctic

Scientists say a long-term shrinking of sea ice on the Arctic Ocean, linked to global warming, exposes warmer water below that releases more heat into the atmosphere. This graphic shows sinking levels of ice since the 1980s

'The question is whether this weather will happen more often. This is just one event so it's hard to make a causal relationship,' he told Reuters.

Scientists say a long-term shrinking of sea ice on the Arctic Ocean, linked to global warming, exposes warmer water below that releases more heat into the atmosphere.

That in turn may be disrupting the high altitude jet stream.

'The jet stream becomes wavier, meaning that colder air can penetrate further south and warmer air further north,' said Nalan Koc, research director of the Norwegian Polar Institute.

Arctic Ocean sea ice is at a record low for late February at 14.1 million square kilometres (5.4 million miles), according to the U.S. National Snow and Ice Data Center.

That is about a million less than normal, or roughly the size of Egypt.

Erik Solheim, head of the U.N. Environment, said the rare weather fits a wider pattern driven by a build-up of greenhouse gases, mainly from burning fossil fuels from cars, factories and power plants.

The last ten days have seen a series of swings near and above freezing at Cape Morris Jesup. This graph shows Danish Meteorological Institute data showing hourly temperature reading in °C historically, in 2017 and in 2018, and on average

The freak warming around the North Pole is sending a blast of Arctic cold over Europe in a sign of 'wacky' weather that may happen more often with global warming. This image shows Nasa satellite imagery of a storm near Greenland that drew a major pulse of warm air into the Arctic

The Cape Morris Jesup is found on the northern tip of Greenland, 442 miles (711.8 km) from the geographic North Pole

'What we once considered to be anomalies are becoming the new normal.

'Our climate is changing right in front of our eyes, and we've only got a short amount of time to stop this from getting significantly worse,' he told Reuters.

Under the 2015 Paris climate agreement, almost 200 nations agreed to limit a rise in temperatures to 'well below' 2°C (3.5°F) above preindustrial times, while pursuing efforts to limit it to 1.5°C (2.7°F).

'The risk of an ice-free Arctic in summer is about 50 per cent or higher' with warming of between 1.5 and 2.0 degrees, according to a leaked draft of a scientific report by a United Nations panel of scientists, obtained by Reuters.

The World Meteorological Organization said the chill in Europe was caused by a 'Sudden Stratospheric Warming' above the North Pole that led to a split in the polar vortex, a cold area of air above the Arctic that spilled cold south.

A big problem in figuring out whether the Arctic warmth is driven by human activities or natural variations is a lack of measuring stations.

There are no thermometers at the North Pole and satellite measurements go back only to the late 1970s.

On the Norwegian archipelago of Svalbard, temperatures were just above freezing, with rain, and about 13.4°C (24°F) above the long-term average on Sunday.

'There have also been recent winters with similar deviations,' said Rasmus Benestad, senior scientist at the Norwegian Meteorological Institute.

U.S. President Donald Trump, who plans to quit the Paris Agreement, has often expressed doubts about mainstream global warming science during cold spells, such as at New Year in the eastern United States.

And Mottram at DMI said Europe's winters had become less severe. 'It's not actually that cold. Its just our perceptions have shifted from a normal winter.'

Wednesday, February 21, 2018

CLIMATE change increases the risk of droughts, heatwaves and flooding by 2051: Here are the cities that will be worse hit

Experts looked at projections from greenhouse gas emissions scenario RCP8.5
This would see a 2.6°C (4.7°F) to 4.8°C (8.6°F) increase in global temperature
Worsening heatwaves are predicted for all 571 European cities studied
Drought conditions would be particularly likely in southern European countries
An increase in river flooding in north-western European cities was forecast

Climate change will bring chaos to Europe by the year 2051, according to a new study that examined the impact of extreme weather events on the continent.

Experts analysed likely changes in flooding, droughts and heatwaves for all European cities using all available climate models.

Worsening heatwaves are predicted for all 571 cities studied, as well as increasing drought conditions, particularly in southern Europe.

An increase in river flooding, especially in north-western European cities like London, was also forecast in simulations.

Climate change will bring chaos to Europe by the year 2051, according to a new study that examined the impact of extreme weather events on the continent. Worsening heatwaves are predicted for all 571 cities studied, as well as increasing drought conditions

Researchers from Newcastle University looked at projections from all models associated with the high greenhouse gas emissions scenario RCP8.5.

This is used by the Intergovernmental Panel on Climate Change (IPCC) and is seen by many as a 'business as usual' scenario, with emissions continuing to grow at current rates.

This would see a 2.6°C (4.7°F) to 4.8°C (8.6°F) increase in global temperature, according to the IPCC.

The team showed results for three possible futures which they called the low, medium and high impact scenarios.

The British Isles has some of the worst overall flood projections. Even in the most optimistic case, 85 per cent of UK cities with a river - including London - are predicted to face increased river flooding.

For the high scenario, half of UK cities could see at least a 50 per cent increase on peak river flows.

The cities predicted to be worst hit under the high impact scenario are Cork, Derry, Waterford, Wrexham, Carlisle and Glasgow and for the more optimistic, low impact, scenario are Derry, Chester, Carlisle, Aberdeen, Glasgow and Newcastle.

By 2051 to 2100, for the low impact scenario, cities in the south of Iberia, such as Malaga and Almeria, are expected to experience droughts more than twice as bad as in 1951 to 2000.

For the high impact scenario, 98 per cent of European cities could see worse droughts in the future. Cities in Southern Europe may experience droughts up to 14 times worse than today (stock image)

While for the high impact scenario, 98 per cent of European cities could see worse droughts in the future.

'Although southern European regions are adapted to cope with droughts, this level of change could be beyond breaking point,' Dr Selma Guerreiro, lead author, said.

'Furthermore, most cities have considerable changes in more than one hazard which highlights the substantial challenge cities face in managing climate risks.'

Even the most optimistic prediction, the low impact scenario, predicts both the number of heatwave days and their maximum temperature will increase for all European cities.

Southern European cities will see the biggest increases in the number of heatwave days, while central European cities will see the greatest increase in temperature during heatwaves.

**COUNTRIES MOST AFFECTED BY EXTREME WEATHER DUE TO CLIMATE CHANGE**
Flooding	Heatwaves	Drought
Dublin	Athens	Athens
Helsinki	Nicosia	Lisbon
Riga	Prague	Madrid
Vilnius	Rome	Nicosia
Zagreb	Sofia	Sofia
	Stockholm	Valleta
	Valleta
	Vienna

Central European cities will see the greatest increase in temperature during heatwaves - between 2°C (3.6°F) to 7°C (12.6°F) for the low scenario and 8°C (14.4°F) to 14°C (25.2°F) for the high scenario.

For changes in droughts and floods, the cities which are affected depend on the scenario.

For the low impact scenario, drought conditions only intensify in southern European cities while river flooding only worsens in north-western ones.

Of the European capitals, Dublin, Helsinki, Riga, Vilnius and Zagreb are likely to experience the most extreme rise in flooding.

For the high impact scenario, several European cities could see more than 80 per cent increases on peak river flows.

That includes Santiago de Compostela in Spain, Cork and Waterford in Ireland, Braga and Barcelos in Portugal and Derry / Londonderry in the UK.

Stockholm and Rome could see the greatest increase in number of heat-wave days while Prague and Vienna could see the greatest increase in maximum temperatures during heat-waves.

Lisbon and Madrid are in the top capital cities for increases in frequency and magnitude of droughts, while Athens, Nicosia, Valleta and Sofia might experience the worst increases in both drought and heatwaves.

The United Nation's Intergovernmental Panel on Climate Change (IPCC) has recognised the important role cites must play in tackling climate change and next month will hold its first Cities and Climate Change Science Conference, in Edmonton, Canada.

'A key objective for this conference is to bring together and catalyse action from researchers, policy makers and industry to address the urgent issue of preparing our cities, their population, buildings and infrastructure for climate change,' said Professor Richard Dawson, co-author and lead investigator of the study, who sits on the Scientific Steering Committee for the IPCC Conference.

'The research highlights the urgent need to design and adapt our cities to cope with these future conditions.

'We are already seeing at first hand the implications of extreme weather events in our capital cities.

'In Paris the Seine rose more than four metres (13 feet) above its normal water level.

'And as Cape Town prepares for its taps to run dry, this analysis highlights that such climate events are feasible in European cities too.'

The full findings were published in the journal Environmental Research Letters.

WHAT WERE GLOBAL TEMPERATURES IN 2017?

Earth’s global surface temperatures in 2017 ranked as the second warmest since 1880, according to an analysis by Nasa.

Continuing the planet's long-term warming trend, globally averaged temperatures in 2017 were 0.90°C (1.62°F) warmer than the 1951 to 1980 average, according to scientists at Nasa’s Goddard Institute for Space Studies (GISS) in New York.

That is second only to global temperatures in 2016.

In a separate, independent analysis, scientists at the National Oceanic and Atmospheric Administration (NOAA) concluded that 2017 was the third-warmest year in their record.

+4

This map shows Earth’s average global temperature from 2013 to 2017, as compared to a baseline average from 1951 to 1980, according to an analysis by Nasa. Yellows, oranges, and reds show regions warmer than the baseline

The minor difference in rankings is due to the different methods used by the two agencies to analyse global temperatures, although over the long-term the agencies’ records remain in strong agreement.

Both analyses show that the five warmest years on record all have taken place since 2010.

Because weather station locations and measurement practices change over time, there are uncertainties in the interpretation of specific year-to-year global mean temperature differences.

Taking this into account, Nasa estimates that 2017’s global mean change is accurate to within 0.1°C, with a 95 per cent certainty level.

'Despite colder than average temperatures in any one part of the world, temperatures over the planet as a whole continue the rapid warming trend we’ve seen over the last 40 years,' said GISS director Gavin Schmidt.