Carbon dioxide levels in the Earth’s atmosphere are higher than they have been for the past 23 million years – and it’s a direct result of human activity, study shows

  • Researchers created a new technique to estimate the atmospheric CO2 levels 
  • These estimates use plant fossils and they go back as far as 23 million years 
  • The current fluctuations in CO2 levels are at a point unseen in geological history

Carbon dioxide levels in the atmosphere are higher than at any point in the past 23 million years – much longer back than previously thought, a new study shows.

Researchers say today’s high levels of CO2 are a direct result of human activity and are fluctuating at a rate never seen before in the geological timeline. 

A team from the University of Louisiana at Lafayette used the fossilised remains of plant tissue to discover the new, much older record high of atmospheric CO2. 

Using a new carbon measuring technique, they were able to look at changes in CO2 in the atmosphere going back much further in history than previously achieved.

The remains of land plants can be used to calculate the amount of CO2 in Earth’s atmosphere, according to the research team, who say it is at its highest level in 23 million years

Study authors said: ‘A common message in use to convey the seriousness of climate change to the public is that carbon dioxide levels are higher today than they have been for the past one million years.’

They used a new novel method to determine that in fact levels are actually higher than they have been for the past 23 million years. 

They are also changing and fluctuating at a rate never before seen in history.

‘The current rise in atmospheric CO2 is the result of human activity,’ said Shubert, when asked about the link between their findings and climate change.

‘This rise is faster than any we have measured across at least the last 23 million years of Earth history,’ the study author added.

‘We infer from our work that even small changes in CO2 can have a measurable impact on ecosystems, both in the past and today.’  

Until now the record has only gone back about a million years, with samples taken from ice cores – the new technique  compares carbon isotopes in plant fossils. 

Researchers created a new timeline and found no evidence for any major fluctuations in CO2 levels like we’re seeing today at any other point in history.

The authors say this suggests that today’s abrupt climate change is unique across recent geologic history and a call for action to tackle the issue before it gets worse. 

They developed a new technique to study the two stable isotopes in carbon and how they change in response to levels of CO2 in the atmosphere. 

The study, published in Geology, then involved measuring the relative amounts of these carbon isotopes in fossilised plants and calculating CO2 concentration of the atmosphere when the ancient plants grew. 

Researchers say today’s high levels of CO2 are a direct result of human activity and are fluctuating at a rate never seen in the geological timeline

Study authors found that ecosystems and temperatures could be much more sensitive to smaller changes in CO2 than previously thought.  

 The substantial global warmth of the middle Pliocene – between 3 and 5 million years ago – and during the middle Miocene – 15 to 17 million years ago – were often studied as a comparison to modern global warming.

Researchers say these periods were associated with only modest increases in CO2. 

‘This suggests present-day CO2 exceeds the highest levels that Earth experienced at least since the Miocene, further highlighting the present-day disruption of long-established CO2 trends within Earth’s atmosphere,’ the team wrote.

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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