On 7 April 2023, the National Oceanic and Atmospheric Administration (NOAA) recorded readings of atmospheric CO₂ at 423.01 parts per million (ppm), the highest level ever in human history.
The media response to this was muted, prompting Greta Thunberg to comment that “I don’t know what is scarier, the fact that atmospheric CO2 just hit the highest level in human history, or that it has gone close to completely unnoticed”.
Highest in human history
NASA’s investigation and analysis of ice core data reveals that over the past 800,000 years at least, atmospheric levels of carbon dioxide have stayed below 300ppm. Since the Industrial Revolution, approximately 200 years ago, carbon dioxide readings in the atmosphere have increased from 280ppm to 423ppm (to use the most recent reading) – an increase of over 50% in just two hundred years.
Why does this matter?
The links between carbon emissions and temperature have already been shown, with NASA bluntly stating that, “Carbon dioxide in the atmosphere warms the planet, causing climate change”. Carbon Brief gives a more nuanced and complete exploration of the linkage between carbon emissions and temperature, where they examine the “role CO2 plays as a ‘control knob’ for the Earth’s climate”. Carbon Brief is clear that, “there is a well-known correlation between temperatures and CO2 concentrations over glacial periods”. And point to the Southern Hemisphere and Antarctica itself, as an example of where this correlation between temperature and carbon dioxide can best be seen.
Sometimes, in different locations, temperature can lag carbon dioxide and other times carbon dioxide can lag temperature, as Carbon Brief notes, therefore it is not quite as simple as saying that there is causation between carbon dioxide and temperature, however there is definite feedback and amplification. “It is challenging to precisely match up CO2 records and temperature records from ice cores as there is a delay between new snowfall on an ice sheet (that traps the air bubbles) and then that snow slowly compressing into ice”. Carbon Brief conclude that small changes can trigger serious consequences:
“This is because human emissions of CO2 and other greenhouse gases push the Earth further out of the range of climate conditions that have characterised the past few million years.”
Reducing carbon emissions is key
The IPCC’s Special report on ‘Global Warming of 1.5°C’ stated “Emissions of greenhouse gases due to human activities, the root cause of global warming, continue to increase, year after year”. And in 2021, they stated that:
“In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years (high confidence).”
Therefore, our new level of 423ppm, by extension, is now the highest level of atmospheric carbon dioxide in the past 2 million years.
The IPCC have also stated that limiting warming, by reducing emissions is now the key priority.
“Carbon dioxide emissions are the main cause of future global warming. Past emissions have brought us to today’s climate, but every tonne of carbon dioxide that we emit into the atmosphere from now on will warm the climate further. Limiting warming depends on how quickly we can stop adding carbon dioxide into the atmosphere.”
‘That dangerous doesn’t become cataclysmic’
Professor Bill McGuire, author of Hothouse Earth and emeritus professor of geophysical and climate hazards at University College London, told Yorkshire Bylines that:
“The most recent carbon dioxide readings simply maintain the steady and remorseless ramping up of atmospheric concentrations that are feeding accelerating global heating and climate breakdown. It is perfectly possible that both carbon emissions and global temperatures are climbing more rapidly than at any point in our planet’s 4.6 billion-year history.
“It is now practically impossible for us to stay below a 1.5C global average temperature rise (since pre-industrial times), so that dangerous climate breakdown is now inevitable. This means it is even more critical that we act to stop every additional 0.1C rise and to prevent every tonne of carbon dioxide being emitted, so as to ensure that dangerous doesn’t become cataclysmic.”
Dr Zack Labe, an atmospheric climate scientist from Princeton University, who is more famous for his polar climate visualisations on social media, also told Yorkshire Bylines:
“Carbon dioxide follows a seasonal cycle due to changes in vegetation growth between the two hemispheres during their respective winter and summer. In other words, this relates to the timing of photosynthesis. Typically, carbon dioxide then reaches its annual maximum during the Northern Hemisphere spring season. However, due to the emission of greenhouse gases from the burning of fossil fuels, we are seeing carbon dioxide levels set higher and higher maximum peaks during this time of year. For example, carbon dioxide as monitored in Mauna Loa, Hawaii was about 419 ppm in March 2022. But this year, it reached 421 ppm in March.
“Without rapidly reducing the amount of future greenhouse gas emissions, carbon dioxide levels will continue to rise and climate models project that our planet will continue to warm in response. This increase in warming will be at a faster rate in some regions, such as over land areas, with impacts to communities around the world. Some of these impacts include the higher chance for extreme heat waves or precipitation events. Climate models also indicate that if carbon dioxide levels are not quickly reduced then there are going to be large consequences in terms of rising global sea levels from melting land ice. Therefore, the next decade is a critical window for reducing greenhouse gas levels, like carbon dioxide.”
How can we reduce carbon emissions?
The solutions to reduce carbon dioxide emissions have already been thankfully agreed by countries around the world in the latest IPCC synthesis report, published last month. The physical methods of halving carbon dioxide emissions by 2030 are already in place – we know what they are. All that is perhaps missing is the political impetus from governments to take the necessary climate action.
At the end of the summary for policy makers in the synthesis report, methods to reduce emissions were signposted. Solar polar and wind power alone could cut 8 billion tonnes of carbon dioxide by 2030. Stopping forest destruction could save another 4 billion tonnes, along with restoration of degraded forests is next on the priority list. Energy efficiency in buildings and lighting could save 4.5 billion tonnes by 2030, while a shift to ‘sustainable diets’ could save almost 2 billion tonnes.
Professor David Ho, of the University of Hawaii, warned in his latest article in Nature, that reducing emissions has to be the priority, rather than attempts to remove carbon from the atmosphere, “Drastically reduce emissions first, or carbon dioxide removal will be next to useless”. He commented that “carbon dioxide removal is not a current climate solution” and added that:
“Humanity has never removed an atmospheric pollutant at a global, continental or, even, regional scale — we have only ever shut down the source and let nature do the clearing up. We have to shift the narrative as a matter of urgency.”
Professor McGuire notes that:
“A good start would be to scrap all new oil, gas and coal developments, to get rid of the huge government subsidies that underpin new fossil fuel initiatives, to ban bank loans to fossil fuel corporations and stop insurers underwriting new fossil fuel facilities. A carbon tax levied at the well-head and mine entrance would be the icing on the cake.”
Is a better climate narrative needed?
There have been several attempts to change the climate story in recent weeks. Both Jonathan Pie and Joanna Haigh, professor emeritus of atmospheric physics at Imperial College London, recently teamed up to ‘translate’ climate science into layman’s terms with a dash of humour. Professor McGuire and Kiri Pritchard-McLean also produced the first comedy video that ‘translated’ much of the information from the synthesis report into a medium for the general public.
Collective climate action to hold attention
From 21-24 April, Extinction Rebellion are calling for 100,000 people to attend ‘The Big One’ in London. This will coincide with Earth Day on 22 April, with the aim that this will be the biggest climate protest ever held in the UK – an event impossible for the UK government to ignore. They state:
“Every single person makes us collectively more powerful, and makes our voices harder for the government to ignore. Just imagine what thousands of us working together could do. We can make this the biggest climate protest ever held in the UK.”
The UK government’s recent ‘Green Day’ analysis showed that it was well off from reducing methane emissions and the government’s net zero strategy also indicates that the UK will miss the necessary 2030 emission cuts target.
Reducing carbon dioxide emissions is not only a legal commitment, but necessary action for the world, especially in a year when fears grow about the potential of a ‘super El Niño’ event.
The activist Sophia Kianni, the youngest member of the United Nations secretary general’s Youth Advisory Group on Climate Change, who spoke to world leaders at COP27, told me:
“As a youth activist, I believe that the latest news about the highest sustained rise of carbon dioxide is extremely concerning. It’s clear that climate change is not a distant problem that we can put off for future generations to deal with. It is a crisis that is affecting us right now and it’s up to all of us to take action. We need to increase public awareness about the severity of this issue and push for more urgent action from our governments and leaders. We need to invest in renewable energy sources and transition off of fossil fuels.”