From the very beginning of the universe, carbon dioxide (CO2) has played a crucial role in shaping the Earth’s climate. Over an expanse of billions of years, atmospheric levels have risen and fallen periodically, resulting in extreme temperature variations.
Since the Industrial Revolution in the mid-1700s, the concentration of CO2 in our air has been rising exponentially, and this trend is continuing at an alarming rate. This is extremely concerning as CO2 is the primary driver of global warming, one of the greatest challenges we currently face.
However, it is not only climate change we need to be concerned about. Indoor levels of CO2 tend to be higher than that outdoors, and as outdoor concentrations continue to rise, this will lead to even greater concentrations in our indoor spaces. This will have a direct impact on our health, leading to heightened issues with cognitive performance and productivity.
In the coming decades, rising levels of CO2 will have an increasingly detrimental effect on both the planet and our own health. Governments, companies and communities need to come together to reduce emissions and protect our future.
The beginning of the Earth
CO2 has been present in our atmosphere since the Earth was formed around 4.5 billion years ago. At this time, the atmosphere consisted mostly of nitrogen, CO2 and water vapour, which seeped through cracks in the solid surface of the planet.
As the Earth continued to cool, some of the water vapour condensed to form oceans, and these vast expanses of water dissolved a portion of the CO2, but it was still present in the atmosphere in large quantities.
Approximately 2.5 billion years ago, plants developed the ability to photosynthesise and this had a completely transformative impact on the atmosphere. As life developed, CO2 was consumed to the extent that by around 20 million years ago, its concentration was down to 300 parts per million (ppm).
Since then, it has gone through peaks and troughs of concentration, but the last time CO2 levels were as high as they are today, humans didn’t even exist.
CO2 and global warming
CO2 plays a pivotal role in controlling our climate as it is one of the atmospheric greenhouse gases (GHGs) which keeps the Earth’s surface about 33 degrees warmer than it would be if they were not present.
In the present climate, the most effective GHGs are water vapour, which is responsible for about two-thirds of the total warming, and CO2 which accounts for about one quarter. Other gases, including methane, nitrous oxide and ozone, make up the remainder.
The overall increase in global temperature of about 1C over the past 150 years is almost solely due to the human activities that have produced increasing amounts of atmospheric GHGs.
CO2 and ice age cycles
Ice ages have occurred roughly every 100,000 years throughout the past 500,000 years. During each of these, global temperatures have dropped by around 5C, with CO2 concentrations falling below 200ppm.
During the most recent ice age, it is thought that low levels of CO2 in the air almost wiped out mankind completely. Extremely cold water in oceans that were 400 feet shallower than today, sucked most of the CO2 from the air, and half of Europe and Asia and North America were buried under mile-high glaciers that obliterated everything in their paths.
The Earth’s atmosphere had only about 180ppm of CO2, compared to today’s level, which averaged 409.8ppm in 2019 globally. Intense cold, permanent drought and CO2 starvation killed the majority of plants, with only a few trees surviving. It is estimated that only 100,000 humans were left alive across the world when the current interglacial warming began.
Why are CO2 levels rising?
CO2 levels have been rising exponentially with a doubling time of about 35 years since the beginning of the Industrial Revolution. This is mostly due to the combustion of fossil fuels, but also a result of large-scale tropical deforestation.
In 2015, levels passed 400ppm, more than 40% higher than its pre-industrial value of 280ppm. If global energy demand continues to grow and to be met mostly with fossil fuels, atmospheric CO2 is projected to exceed 900ppm by the end of this century.
What does this mean for the planet?
Increases in atmospheric CO2 not only lead to an increase in air temperature, but also cause the oceans to warm and expand. This contributes to rising sea levels, which is further exacerbated by the melting of land-based ice, like glaciers and ice sheets. The warmer atmosphere is also causing more extreme weather patterns across the world, including floods and droughts.
If human emissions of GHGs continue to rise at their current rate, the global temperature will continue to increase and the associated weather impacts will become ever more severe.
In Paris in 2015, 195 countries agreed to limit global heating ‘well below 2C’, striving towards 1.5ºC. This was an extraordinary political achievement, but drastic steps need to be taken on a global basis to address the escalating crisis. Efforts have also been hampered by Donald Trump who has made various comments dismissing climate change as ‘mythical’ and ‘a very expensive hoax’, and has taken steps to remove the U.S. from the Paris agreement.
The world needs an urgent transition from fossil fuels to renewable energy. Data shows that the energy transition is happening far too slowly, with the Production Gap Report showing that the world is currently on track to produce 120 percent more fossil fuels by 2030 than is compatible with a 1.5ºC increase in temperature.
There are also many simple things we can all do in everyday life to make a difference. This includes putting pressure on governments and companies, reducing use of cars and planes where possible, using renewable energy and reducing our consumption of animal protein. This article provides some great detail on how our actions can have a positive impact on climate change.
What does this mean for indoor spaces?
While we are all aware that atmospheric levels of CO2 are rising, something that is less widely known is the fact that this is actually likely to make intellectual impairment a far more widespread problem in the decades ahead.
A paper published by academics from the UCL Energy Institute looked at how elevated levels of atmospheric CO2 might impact air quality in offices.
They found that by the end of the century, on a business-as-usual projection of global CO2 emissions, it will become impossible to maintain current limits on indoor CO2 concentration without resorting to significantly more expensive approaches, like CO2 removal.
In the decades to come, the climate crisis will be increasingly accompanied by a productivity crisis in our indoor spaces.
What does CO2 actually do to our brain?
We all know the feeling of being stuck in a crowded room and feeling increasingly tired and finding it difficult to concentrate.
According to the American Society of Heating, Refrigeration and Air-Conditioning Engineers, 1000ppm is the threshold at which a room starts feeling stuffy for most people, and levels in indoor spaces routinely exceed this. This article gives an interesting real-life example of an astronomer taking a CO2 monitor to a packed lecture hall in Helsinki and tracking the changes across the day.
Increased levels of CO2 in our blood decrease the cerebral metabolism of oxygen. To put it simply, the brain becomes deprived of oxygen and this has an impact on our thinking abilities.
CO2 dissolves in blood and then reacts with the water in our blood to create carbonic acid. This, in turn, dissolves into ions of hydrogen and bicarbonate. If there’s an increase in the concentration of hydrogen ions in our blood, the blood acidity level increases and creates an electrolyte imbalance. This imbalance causes increased discomfort and a significant decline in intellectual performance.
How much does CO2 impact productivity?
Even a seemingly insignificant rise in CO2 can make an important difference to our productivity.
A British Council for Offices study showed that with lower CO2 levels, employees’ test scores improved by up to 12%. In one of the buildings tested, people worked 60% faster with reduced CO2 concentrations, completing tests in a mean time of 8.2 minutes, compared with 13.3 minutes with more CO2 in the atmosphere.
Another study by the World Green Building Council found that by increasing ventilation and lowering levels of CO2 in the workplace from 1000ppm to to 500-600ppm, there was an 8-11% improvement in productivity.
Why do CO2 levels tend to be high in the workplace?
There is an abundance of research showing that we need fresh air to perform to the best of our ability. It is therefore ironic that offices – spaces that are specifically designed with work and productivity in mind – often tend to be the most guilty of high CO2 levels.
Due to energy efficiency concerns, opening windows in offices is usually highly controlled. New offices are built to be airtight and the quality of the indoor air is heavily reliant on ventilation and air conditioning.
This can be problematic as even if buildings meet ventilation standards, this doesn’t mean that high CO2 levels are being detected and reduced. As a result, office spaces are often inadvertently detrimental to the productivity and cognitive function of employees.
How can indoor CO2 levels be controlled?
As things currently stand, controlling levels of CO2 can be fairly straightforward. Ventilation is the key to reducing CO2 and creating a healthier indoor environment. As outdoor air is brought inside, CO2 naturally dilutes and becomes less concentrated.
In offices and commercial buildings, sensors connected to a platform can monitor air quality in real-time, raising alerts when CO2 starts to rise. Ventilation can then be increased when necessary to maintain a healthy and productive indoor environment.
When you’re working from home, it might not be economically viable to install CO2 sensors yourself, and the majority of homes in the UK do not have mechanical ventilation systems or air conditioning. However, unlike offices, it’s usually fairly easy to open a window, a quick and easy way to reduce CO2 levels. Our Journal post on how you can make low-cost operational changes to improve your Indoor Air Quality could be a good place to start.
How will this change in the coming decades?
A research paper has predicted that if outdoor CO2 concentrations rise to 930ppm by the end of the century, this will push indoor concentrations to a harmful level of 1400ppm.
Although increasing ventilation is currently a suitable measure to reduce indoor levels, this will become less helpful as outdoor concentrations increase. Furthermore, if ventilation rates are forced to increase significantly, this will lead to greater energy consumption.
Taking steps to monitor and reduce indoor CO2 levels is only going to become more vital as outdoor levels continue to rise. What is concerning is that keeping levels down is going to become much more costly, difficult, and environmentally problematic.
What does the future look like?
One silver lining of the COVID-19 pandemic is a projected 8% drop in global CO2 emissions in 2020. Alarmingly, this scarcely takes emissions back to where they were a decade ago, and this same decline would be needed every year until 2050 to limit the rise in global temperatures in line with the Paris Agreement.
We need to use the current crisis as an opportunity to reposition the global economy for a greener future. Now is the time to shift the trajectory on rising CO2 levels to avoid both a climate and productivity crisis in the near future.