Why are Spain and Portugal so unbelievably hot right now?

Wildfires in the Algarve, Portugal, last weekend. Image: Getty.

Wildfires, drought and extreme heat have been the talk of the town and country across Europe this summer. Attention has now turned to Portugal and Spain, where temperatures at the weekend reached more than 46℃ in some parts of both countries – close to the all-time European record of 48℃, set in Greece in 1977. Records aside, the obvious question is what is causing the current Iberian heatwave and whether this might be a harbinger of the future.

A number of factors can be identified. These include unusually warm sea surface temperatures in the North Atlantic, a wandering jet stream and associated “blocking” pattern of high pressure, a very dry land surface, and climate change.

The anomalous size and position of warm water areas in the North Atlantic this summer have shifted the so-called “polar front” northwards. This is the point where warm air from the south meets cold polar air, and any movement in the front will affect the distribution of high and low atmospheric pressure right across the Atlantic. This in turn influences the flow of westerly winds across the Atlantic and over Western and Southern Europe, especially the thin and fast “jet stream” in the upper atmosphere.

This summer, an area of persistent high pressure or “blocking” has become established over Western Europe and the eastern parts of the Atlantic. Such blocking causes the jet stream to appear “lazy” and wander much further north and south than its average position.

Maximum temperatures for 6 August, with large areas well into the 40s. Image: Agencia Estatal de Meteorología (AEMET).

The upshot of all of this is that atmospheric blocking and a very snake-like jet stream prevents low pressure systems, and the “bad” weather they bring, from heading eastwards across Western and Southern Europe. In such a situation, the usual fluctuations between good, and not so good, summer weather are largely put on hold. Instead, as Portugal, Spain and much of Europe have experienced, clear skies, lots of heat, and very dry surface conditions become the norm.

In certain circumstances, persistent blocking can even draw in very warm air from elsewhere. This is what happened in Portugal and Spain, after intense heat caused an area of low pressure to form over Iberia. This “heat low” created the conditions for the flow of hot dry air from the Saraha Desert. Currently life in Portugal and Spain is not just in an oven, but more like a convection oven.


A warmer baseline means hotter extremes

Heatwaves in Portugal and Spain are not uncommon because this type of extreme weather is characteristic of the hot and dry summers in the Mediterranean climate region. Yet there is convincing observational evidence that heatwaves are happening more frequently across the Iberian Peninsula. Logically the question arises as to what extent the current heat is associated with climate change.

Although answering this question thoroughly would involve undertaking some well-designed climate modelling experiments, it’s safe to say that there is indeed a fair chance the current heatwave is associated with climate change. That is because heatwaves are now happening on a background of rising global temperatures so the base level of background temperature on which extremes are occurring has lifted somewhat compared to pre-industrial levels.

And what of the question on everyone’s parched lips: are the current extremes the “new norm”? The short answer is no, not right now, as extremes of over 46℃ still constitute rare events. However, analyses of the pronounced 2003 European heat wave, which affected both Portugal and Spain, indicate that the very similar extremes of August 2003 could be fairly normal by the 2040s.

The ConversationThis of course raises questions as to the habitability of places that already possess harsh summer climates. Most likely their sustainability will depend on the extent to which traditional climate adaptation strategies related to building and lifestyles can be pushed to the limit to cope with a new climate future typified by summers with temperatures in and over the mid 40s - and how flexible people and businesses might be to the idea of going elsewhere or literally underground during summer.

Glenn McGregor, Professor of Climatology, Durham University.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Covid-19 is highlighting cities' unequal access to green space

In the UK, Londoners are most likely to rely on their local park for green space, and have the best access to parks. (Leon Neal/Getty Images)

As coronavirus lockdowns ease, people are flooding back to parks – but not everyone has easy access to green space in their city.

Statistics from Google show that park attendance in countries across the globe has shot up as people have been allowed to move around their cities again.

This is especially true in urban areas, where densely populated neighbourhoods limit the size of private green space – meaning residents have to go to the park to get in touch with nature. Readers from England can use our interactive tool below to find out how much green space people have access to in their area, and how it compares to the rest of the country.

 

Prime Minister Boris Johnson’s announcement Monday that people are allowed to mingle in parks and gardens with groups of up to six people was partially following what people were doing already.

Data from mobile phones show people have been returning to parks across the UK, and also across Europe, as weather improves and lockdown eases.

People have been returning to parks across the world

Stay-at-home requirements were eased in Italy on 4 May, which led to a flood of people returning to parks.

France eased restrictions on 1 May, and the UK eased up slightly on 13 May, allowing people to sit down in public places so long as they remain socially distanced.

Other countries have seen park attendance rise without major easing of lockdown – including Canada, Spain, and the US (although states there have individual rules and some have eased restrictions).

In some countries, people never really stopped going to parks.

Authorities in the Netherlands and Germany were not as strict as other countries about their citizens visiting local parks during lockdown, while Sweden has famously been avoiding placing many restrictions on people’s daily lives.


There is a growing body of evidence to suggest that access to green space has major benefits for public health.

A recent study by researchers at the University of Exeter found that spending time in the garden is linked to similar benefits for health and wellbeing as living in wealthy areas.

People with access to a private garden also had higher psychological wellbeing, and those with an outdoor space such as a yard were more likely to meet physical activity guidelines than those without access to outdoor space. 

Separate UK research has found that living with a regular view of a green space provides health benefits worth £300 per person per year.

Access is not shared equally, however, which has important implications for equality under lockdown, and the spread of disease.

Statistics from the UK show that one in eight households has no garden, making access to parks more important.

There is a geographic inequality here. Londoners, who have the least access to private gardens, are most likely to rely on their local park for green space, and have the best access to parks. 

However the high population in the capital means that on the whole, green space per person is lower – an issue for people living in densely populated cities everywhere.

There is also an occupational inequality.

Those on low pay – including in what are statistically classed as “semi-skilled” and “unskilled” manual occupations, casual workers and those who are unemployed – are almost three times as likely as those in managerial, administrative, professional occupations to be without a garden, meaning they rely more heavily on their local park.

Britain’s parks and fields are also at significant risk of development, according to new research by the Fields in Trust charity, which shows the number of people living further than a 10-minute walk from a public park rising by 5% over the next five years. That loss of green spaces is likely to impact disadvantaged communities the most, the researchers say.

This is borne out by looking at the parts of the country that have private gardens.

The least deprived areas have the largest gardens

Though the relationship is not crystal clear, it shows at the top end: Those living in the least deprived areas have the largest private green space.

Although the risk of catching coronavirus is lower outdoors, spending time in parks among other people is undoubtedly more risky when it comes to transmitting or catching the virus than spending time in your own outdoor space. 

Access to green space is therefore another example – along with the ability to work from home and death rates – of how the burden of the pandemic has not been equally shouldered by all.

Michael Goodier is a data reporter at New Statesman Media Group, and Josh Rayman is a graphics and data visualisation developer at New Statesman Media Group.