Nights are getting warmer at a faster rate than days across much of the planet due to increasing cloud cover, scientists warned

  • Researchers looked at temperature, cloud cover and humidity from 1983 to 2017 
  • They found higher night-time warming is more common than daytime warming 
  • This has created a phenomenon called ‘warming asymmetry’ around the world
  • Higher night-time temperatures causes problems for nocturnal creatures 

The nights are warming up at a faster rate than days across most of the planet due to changing cloud cover – and it is caused by global warming, scientists have warned. 

Researchers from the University of Exeter examined hourly records of temperature, cloud cover, humidity and precipitation around the world from 1983 to 2017.

Night-time warming is more common than daytime warming across 53 per cent of all land surfaces – a phenomenon dubbed ‘warming asymmetry’ by the team.

Temperatures at night were on average ‘disproportionately’ warmer – by about 0.45F – when compared to those during the day as a result of a changing climate. 

This higher night-time temperatures could have ‘potentially significant implications’ for nocturnal species and even the rate of vegetation growth, authors warned.  

Different parts of the world are experiencing changes in cloud cover at different rates and this is creating an asymmetry in warming that is impacting nocturnal species

The researchers believe the warming asymmetry phenomenon they observed over 30 years of data is being driven primarily by changes in cloud cover.

Clouds cool the planet’s surface during the day but retain the warmth during the night, leading to greater night-time warming.

In contrast, a lack of clouds allow more warmth to reach the surface during the day, but that heat is lost at night.

Lead author Dr Daniel Cox, of the Environment and Sustainability Institute on Exeter’s Penryn Campus in Cornwall, said greater night-time warming is associated with the climate becoming wetter.

‘This has been shown to have important consequences for plant growth and how species, such as insects and mammals, interact,’ he explained.

‘Conversely, we also show that greater daytime warming is associated with drier conditions, combined with greater levels of overall warming, which increases species vulnerability to heat stress and dehydration.

‘Species that are only active at night or during the day will be particularly affected.’

He added: ‘Warming asymmetry has potentially significant implications for the natural world,’ including changes in vegetation growth. 

The researchers believe the warming asymmetry phenomenon they observed over 30 years of data is being driven primarily by changes in cloud cover

The authors created simulations to show different rates of change to day and night-time maximum temperatures – as well as cloud cover, humidity and precipitation. 

Comparing real data to their simulations they were able to track the impact of a changing climate on global temperatures and the level of cloud cover.   

The study team also looked at changes in vegetation growth and rainfall over the same 30 years period and found differences in day and night-time growth rates. 

Increased night-time warming led to less vegetation growth where it rained more, likely due to increased cloud cover blocking the sun.

Whereas, vegetation growth was limited by water availability due to less rainfall where the days warmed more.

The findings have been published in the journal Global Change Biology. 

Revealed: MailOnline dissects the impact greenhouse gases have on the planet – and what is being done to stop air pollution

Emissions

Carbon dioxide

Carbon dioxide (CO2) is one of the biggest contributors to global warming. After the gas is released into the atmosphere it stays there, making it difficult for heat to escape – and warming up the planet in the process. 

It is primarily released from burning fossil fuels such as coal, oil and gas, as well as cement production. 

The average monthly concentration of CO2 in the Earth’s atmosphere, as of April 2019, is 413 parts per million (ppm). Before the Industrial Revolution, the concentration was just 280 ppm. 

CO2 concentration has fluctuated over the last 800,000 years between 180 to 280ppm, but has been vastly accelerated by pollution caused by humans. 

Nitrogen dioxide 

The gas nitrogen dioxide (NO2) comes from burning fossil fuels, car exhaust emissions and the use of nitrogen-based fertilisers used in agriculture.

Although there is far less NO2 in the atmosphere than CO2, it is between 200 and 300 times more effective at trapping heat.

Sulfur dioxide 

Sulfur dioxide (SO2) also primarily comes from fossil fuel burning, but can also be released from car exhausts.

SO2 can react with water, oxygen and other chemicals in the atmosphere to cause acid rain. 

Carbon monoxide 

Carbon monoxide (CO) is an indirect greenhouse gas as it reacts with hydroxyl radicals, removing them. Hydroxyl radicals reduce the lifetime of carbon dioxide and other greenhouse gases. 

Particulates

What is particulate matter?

Particulate matter refers to tiny parts of solids or liquid materials in the air. 

Some are visible, such as dust, whereas others cannot be seen by the naked eye. 

Materials such as metals, microplastics, soil and chemicals can be in particulate matter.

Particulate matter (or PM) is described in micrometres. The two main ones mentioned in reports and studies are PM10 (less than 10 micrometres) and PM2.5 (less than 2.5 micrometres).

Air pollution comes from burning fossil fuels, cars, cement making and agriculture 

Scientists measure the rate of particulates in the air by cubic metre.

Particulate matter is sent into the air by a number of processes including burning fossil fuels, driving cars and steel making.

Why are particulates dangerous?

Particulates are dangerous because those less than 10 micrometres in diameter can get deep into your lungs, or even pass into your bloodstream. Particulates are found in higher concentrations in urban areas, particularly along main roads. 

Health impact

What sort of health problems can pollution cause?

According to the World Health Organization, a third of deaths from stroke, lung cancer and heart disease can be linked to air pollution. 

Some of the effects of air pollution on the body are not understood, but pollution may increase inflammation which narrows the arteries leading to heart attacks or strokes. 

As well as this, almost one in 10 lung cancer cases in the UK are caused by air pollution. 

Particulates find their way into the lungs and get lodged there, causing inflammation and damage. As well as this, some chemicals in particulates that make their way into the body can cause cancer. 

Deaths from pollution 

Around seven million people die prematurely because of air pollution every year. Pollution can cause a number of issues including asthma attacks, strokes, various cancers and cardiovascular problems. 

 

Asthma triggers

Air pollution can cause problems for asthma sufferers for a number of reasons. Pollutants in traffic fumes can irritate the airways, and particulates can get into your lungs and throat and make these areas inflamed. 

Problems in pregnancy 

Women exposed to air pollution before getting pregnant are nearly 20 per cent more likely to have babies with birth defects, research suggested in January 2018.

Living within 3.1 miles (5km) of a highly-polluted area one month before conceiving makes women more likely to give birth to babies with defects such as cleft palates or lips, a study by University of Cincinnati found.

For every 0.01mg/m3 increase in fine air particles, birth defects rise by 19 per cent, the research adds. 

Previous research suggests this causes birth defects as a result of women suffering inflammation and ‘internal stress’. 

What is being done to tackle air pollution? 

Paris agreement on climate change

The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change. 

It hopes to hold the increase in the global average temperature to below 2°C (3.6ºF) ‘and to pursue efforts to limit the temperature increase to 1.5°C (2.7°F)’.

Carbon neutral by 2050 

The UK government has announced plans to make the country carbon neutral by 2050. 

They plan to do this by planting more trees and by installing ‘carbon capture’ technology at the source of the pollution.

Some critics are worried that this first option will be used by the government to export its carbon offsetting to other countries.

International carbon credits let nations continue emitting carbon while paying for trees to be planted elsewhere, balancing out their emissions.

No new petrol or diesel vehicles by 2040

In 2017, the UK government announced the sale of new petrol and diesel cars would be banned by 2040. 

From around 2020, town halls will be allowed to levy extra charges on diesel drivers using the UK’s 81 most polluted routes if air quality fails to improve.

However,  MPs on the climate change committee have urged the government to bring the ban forward to 2030, as by then they will have an equivalent range and price.

The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change. Pictured: air pollution over Paris in 2019.

Norway’s electric car subsidies

The speedy electrification of Norway’s automotive fleet is attributed mainly to generous state subsidies. Electric cars are almost entirely exempt from the heavy taxes imposed on petrol and diesel cars, which makes them competitively priced.

A VW Golf with a standard combustion engine costs nearly 334,000 kroner (34,500 euros, $38,600), while its electric cousin the e-Golf costs 326,000 kroner thanks to a lower tax quotient. 

Criticisms of inaction on climate change

The Committee on Climate Change (CCC) has said there is a ‘shocking’ lack of Government preparation for the risks to the country from climate change. 

The committee assessed 33 areas where the risks of climate change had to be addressed – from flood resilience of properties to impacts on farmland and supply chains – and found no real progress in any of them.

The UK is not prepared for 2°C of warming, the level at which countries have pledged to curb temperature rises, let alone a 4°C rise, which is possible if greenhouse gases are not cut globally, the committee said.

It added that cities need more green spaces to stop the urban ‘heat island’ effect, and to prevent floods by soaking up heavy rainfall. 

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