Earth is DIMMING due to climate change: Warming oceans cause fewer bright clouds to reflect sunlight into space – trapping even more energy in our planet, study warns
- Researchers made use of decades of measurements of earthshine and clouds
- Earthshine is the light reflected from the Earth to illuminate the lunar surface
- It allows the team to see how much solar radiation is reflected from the Earth
- They found a notable drop in the Earth’s reflected light in their measurements
- This means more solar radiation is entering the Earth and could warm the air
Earth is dimming as the warmer oceans are causing fewer bright clouds to reflect sunlight into space, trapping more energy in our planet, a new study has warned.
Decades of measurements of earthshine – the light reflected from Earth that illuminates the surface of the moon – allowed the team from the New Jersey Institute of Technology to get a better picture of the impact of climate change.
They also made use of satellite measurements to discover that there has been ‘a significant drop in Earth’s reflectance’, or albedo, over the past two decades.
The Earth is now reflecting about half a watt less light per square metre than it was 20 years ago, according to the researchers.
The team said that half the drop in light happened in the past three years, after 17 years of flat albedo, mainly due to fewer low-lying clouds over the Pacific Ocean.
Scientists had hoped that a warmer Earth caused by climate change would create more clouds, and a higher albedo to moderate the warming, but the opposite appears to be happening, which could accelerate climate change.
The Earth is dimming as the warmer oceans are causing fewer bright clouds to reflect sunlight into space, trapping more energy in our planet, a study warns
Decades of measurements of earthshine (blue dots) – the light reflected from Earth that illuminates the surface of the moon – allowed the team from the New Jersey Institute of Technology to get a better picture of the impact of climate change
WHAT IS ALBEDO?
Albedo is a measure of the reflection of solar radiation from the Earth.
It is taken on a scale of zero to one, where one is white and zero is black.
A black body absorbs all incident radiation, and includes things like water, crops and forests.
At the other end of the scale, a white body reflects solar radiation into space, including snow and clouds.
Albedo is important in climatology, astronomy, and environmental management.
Earth’s average albedo is 30 to 35 per cent, fluctuating depending on the activity levels of the Sun.
It can also vary widely at a local level depending on cloud cover.
Climate change is causing some atmospheric changes, reducing cloud cover over some areas, and leading to a lower albedo.
This means that more of the Sun’s energy is entering the Earth and could result in warming oceans and overll higher average global temperatures.
If this happens, it would work to speed up and make climate change worse.
The team found that the Earth’s reflectance had dropped by about 0.5 per cent in the past three years – now reflecting 29.5 per cent of all sunlight.
‘The albedo drop was such a surprise to us when we analysed the last three years of data after 17 years of nearly flat albedo,’ said Philip Goode, lead author.
He was referring to the earthshine data from 1998 to 2017 that had been gathered by the Big Bear Solar Observatory in Southern California.
When the latest data was added to the previous years, the dimming trend became clear to the team.
Two things affect the net sunlight reaching the Earth: the Sun’s brightness and the planet’s reflectivity.
The changes in Earth’s albedo observed by the researchers did not correlate with periodic changes in the Sun’s brightness, so that means changes in Earth’s reflectiveness are caused by something on the Earth.
When looking for obvious changes in other observations that could result in this change in albedo, the team turned to NASA satellites.
Satellite measurements made as part of NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project, revealed a reduction of bright, reflective low-lying clouds over the eastern Pacific Ocean in the most recent years.
That’s the same area, off the west coasts of North and South America, where increases in sea surface temperatures have been recorded.
This increase is down to the reversal of a climatic condition called the Pacific Decadal Oscillation, with likely connections to global climate change.
The dimming of the Earth can also be seen in terms of how much more solar energy is being captured by Earth’s climate system.
Once this significant additional solar energy is in Earth’s atmosphere and oceans, it may contribute to global warming, as the extra sunlight is of the same magnitude as the total human caused climate change over the last two decades, they said.
This matches the findings of a NASA study published in June, that found the Earth’s energy imbalance had doubled from 2005 to 2019.
This means more energy is being absorbed from the Sun than is reflected back to space, throwing the Earth’s energy ‘out of balance’ and warming the planet.
The Earth’s positive energy imbalance is due to increasing atmospheric pollution in the form of greenhouse gases like carbon dioxide (CO2), methane (CH4) and ozone (O3), researchers say.
The team said that half the drop in light happened in the past three years, after 17 years of flat albedo – mainly due to fewer low-lying clouds over the Pacific Ocean
These pollutants block the Earth’s radiant heat from escaping into space, increasing absorption of sunlight and trapping heat within the atmosphere.
Unless the rate of heat uptake subsides, greater changes in climate than are already occurring should be expected, the experts warn.
‘It’s actually quite concerning,’ said Edward Schwieterman, a planetary scientist at the University of California at Riverside who was not involved in the new study.
For some time, many scientists had hoped that a warmer Earth might lead to more clouds and higher albedo, which would then help to moderate warming and balance the climate system, he said. ‘But this shows the opposite is true.’
The findings have been published in the journal Geophysical Research Letters.
Revealed: MailOnline dissects the impact greenhouse gases have on the planet – and what is being done to stop air pollution
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.
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 (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 (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.
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.
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.
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.
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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