Nine key ‘tipping points’ that will lead to catastrophic global warming have been reached, a group of leading scientists have warned.
Scientists say that in these areas sufficient damage has been done that the effects of global warming could accelerate and create a ‘cascade’ effect.
Because tipping points have been crossed, it could lead to a domino effect, accelerating global warming impacts, threatening human existence, scientists warn.
‘The situation is urgent and we need an emergency response’, said said Tim Lenton, head of the University of Exeter team behind this study.
‘The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see what happens.’
In the journal Nature, the scientists said urgent action was needed to reduce greenhouse gas emissions – as other key tipping points, that have not yet been activated could soon be hit.
Other tipping points not currently activated include heating up of deep water in the Antarctic, and the release of methane stored in the Ocean in polar regions.
They also identified a reduction in rainfall in the Indian monsoon, and a major loss of oxygen in the ocean as potential areas of risk.
WHAT ARE THE ACTIVE TIPPING POINTS?
- Arctic sea ice
- Greenland ice sheet
- Boreal forests
- Permafrost Atlantic
- Meridional Overturning Circulation
- Amazon rainforest
- Warm-water corals
- West Antarctic Ice Sheet
- Parts of East Antarctica
Professor Lenton said: ‘A decade ago we identified a suite of potential tipping points in the Earth system, now we see evidence that over half of them have been activated.’
His co-author Johan Rockström, of the Potsdam Institute for Climate Impact Research, said it was not only human pressures on Earth that continue to rise at unprecedented levels.
‘It is also that as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming.
‘This is what we now start seeing, already at 1°C global warming.
‘Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet.’
The collapse of major ice sheets on Greenland, West Antarctica and part of East Antarctica would result in around 10 metres of irreversible sea-level rise.
Despite most countries having signed the Paris Agreement, pledging to keep global warming well below 2°C, current national emissions pledges – even if they are met – would lead to 3°C of warming.
Although future tipping points and the interplay between them is difficult to predict, the scientists argue: ‘If damaging tipping cascades can occur and a global tipping cannot be ruled out, then this is an existential threat to civilisation.
‘No amount of economic cost-benefit analysis is going to help us. We need to change our approach to the climate problem.’
Professor Lenton added: ‘We might already have crossed the threshold for a cascade of inter-related tipping points.
‘However, the rate at which they progress, and therefore the risk they pose, can be reduced by cutting our emissions.’
Though global temperatures have fluctuated over millions of years, the authors say humans are now ‘forcing the system’.
‘With atmospheric carbon dioxide concentration and global temperature increasing at rates that are an order of magnitude higher than at the end of the last ice age.’
Will Steffen professor of climate and Earth system science at the Australian National University said the study shows two of the tipping points – coral reefs and Arctic sea ice – may have already been tipped.
‘The consequence of activating such a cascade would be an unstoppable slide into hothouse Earth conditions.
‘The schoolchildren are right – we indeed have a climate emergency, and an emergency-level response is now needed to ensure that we don’t activate the tipping cascade.’
The research has been published in the journal Nature.
WHAT IS 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).
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.
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.
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.