The Problem with Carbon Dioxide, and what to do about it
Green House Gases, mainly Carbon Dioxide (CO2) in the atmosphere heats up the earth by reflecting radiation back down, like, well, the glass panels in a green house. The higher the concentration of CO2, the more heat is reflected. We currently have a higher concentration of CO2 in the atmosphere than we have seen for maybe 25 million years, mostly because of our burning of fossil fuels. This already high concentration of CO2 is sadly continuing to increase rapidly, which will lead to an accelerated change in our climate, altering the very conditions for life on this planet as we know it. We have already seen man-made temperature increases of more than 1,2 degree Celsius over the past decades, unevenly distributed, meaning some areas, notably the Arctic, have seen much higher temperature rises. This is however nothing to what we are gearing up for over the years to come with the current emissions trajectory. As if we were sitting in a sinking ship on the middle of the ocean, we need to do two things right now: seal the leaks (stop emitting fossil fuels) and start pumping the water out (removing the CO2 from the atmosphere). Thiazzi offers a solution for the latter. We have absolutely no time to spare.
A brief history of CO2 concentrations
Over a time horizon that we can measure quite precisely from ice cores, a million years or so, the concentration of CO2 has been stable between around 200 parts per million (ppm) during ice ages, about 100 000 years long, and up to 300 ppm between ice ages, such as during the last 12000 years. This has resulted in a remarkably steady and constant climate
Since we started burning oil, coal and gas at scale a bit more than 100 years ago, the CO2 concentration in the atmosphere has however increased sharply, up to almost 415 ppm on average today, currently increasing with about 3 ppm per year, at an increasing pace. With current emissions, we will reach 500 ppm well before 2050, then 1000 ppm at the turn of the century, then more.
Now, in the long scale, the earth has for sure had even higher concentrations of CO2 in the past. 400 million years ago, it may have been well over 3000 ppm. Luckily, for us, the solar radiation was also lower back then, meaning the planet did not fry completely, although it was of course much warmer. The last time the CO2 concentration was steadily above 400 ppm was about 25 million years ago, when CO2 levels rose rapidly (well, it took millennia) from roughly pre-industrial levels to well over 1000 ppm, most likely due to massive volcanic activity. Exactly what earth was like back then is not easy to model, but temperatures were likely some ten degrees higher, water levels were tens of meters higher, and we had a very different plant and animal life. To put things in perspective, this was not too long after the dinosaurs died, and millions of years before the first apes. Since the planet as we know it started to take shape, our climate and CO2 levels have been remarkably steady at up to around 300 ppm. Until now.
Forecasts of CO2 emissions, and related temperature increases
There are a number of well-established scenarios for possible future CO2 emissions. None of them is particularly promising reading, but some are worse than others are. Based on the CO2 emissions, the resulting concentration of CO2 in the atmosphere is straightforward to calculate (well, it is actually quite complex, since a lot of CO2 emitted, thankfully, is absorbed by the oceans and biomass, but anyhow). And knowing future scenarios of CO2 in the atmosphere, the resulting temperature increase can be assessed (even more complex, since we’re trying to build climate models for the entire planet earth, with a lot of things acting at the same time. Given the importance of this topic, we have a few thousand climatologists and meteorologist working on the topic though, and sadly, they are in increasing agreement about what the future holds).
The Intergovernmental Panel of Climate Change (IPCC), widely seen as the predominant international authority on climate change, uses “Representative Concentration Pathways” (RCP) to analyze our future. These are technically driven by the additional reflective radiation by the year 2100 (8,5W/m2 in the red scenario, 2,6W/m2 in the lowest blue), and they correspond to different CO2 concentrations by the end of the century (actually sometime between 2080 and 2100). The scenarios are as follows:
Red: More than 1000 ppm by 2100. The world continues as today: population increasing, heavily reliance on fossil fuels, limited real impact of climate politics and actions. Emissions more than double, but still level out by the end of the century (no scenario dares to assume continued growth), but they not decrease. Temperature increase likely somewhere between almost 4 and more than 5°C. This is sadly the trajectory we are on right now.
Grey: 720-1000 ppm. Fossil fuels continue to increase, however at a much slower pace, until 2080, then rapidly falls to 2040 levels as climate politics and renewables outnumbers oil, gas and coal. Temperature increase from more than 2 to almost 4 °C.
Yellow: 480-720 ppm. Extensive and powerful climate politics, electrification of transport, total build out of renewables globally, and changed land use makes CO2 emissions peak at 2040, and then rapidly decreases. Temperature increase roughly between 2 and 3°C.
Blue: 430-480 ppm. Carbon Dioxide emissions peaks in some magical way next year (2020) and starts do decrease drastically thereafter, becoming negative by 2080. Sorry to say, this is most likely not going to happen as the world looks right now. Temperature increases would be limited to about 2°C though, twice what we have seen so far. Still a lot, but nice and cool compared to the other scenarios.
To add to this, there are a few further things to consider. The world does (hopefully) not cease to exist 2100; hence, all scenarios with any emission left will continue to increase the concentration of CO2 in the atmosphere further. Moreover, right now, we are not even slowing down the increase. Rather, the rate of increase, is increasing. In addition, the temperature increase is not evenly distributed on the planet. Displaying on a world map the red (current trajectory) and blue scenarios, it becomes obvious that our children’s children will be playing on quite different fields if we continue as now. To put this in some kind of perspective; the average annual temperature difference between Nepal, in the snow covered Himalayas, and Morocco, just north of the Sahara Desert in Africa, is about nine degrees
Consequences of rising temperatures
So what if temperatures are increasing? We already live in a 1.2 degree warmer world than our grandparents did. How bad can it be? Well, the answer is; Pretty bad. Putting the future red (business as usual) and blue (unrealistically optimistic) scenarios in a 400 million year perspective, it looks something like this:
Even if we stop the curve at roughly the year 2200, we are looking at CO2 levels that we have not seen for hundreds of millions of years on Earth. This would lead to a completely different planet. It is hard to know exactly what kind of planet, but since the sun is warmer today than back then, the radiating effect would be higher than what we have ever seen, including when life emerged on land. Temperatures would be 10+ degrees warmer on average. There would obviously be no ice on land, meaning sea levels will rise about 70 meters over time. Large swathes of earth will likely be uninhabitable. Our food production systems will be all but wiped out. Worse though, is the speed of change. When CO2 levels have changed historically, this has taken thousands to millions of years, meaning animal and plant life have had the chance to adapt. Change at this scale in a few hundred years likely mean mass extinction at a scale unprecedented. Earth’s climate have seen a handful of drastic changes over the past hundreds of millions of years, and as a consequence, 75-90% of species have been wiped out. This time, we are however changing the climate several thousand times faster. That the coral reefs will be long gone, while forest fires, hurricanes, floods and droughts will be commonplace, at the same time as water and food shortage will lead to social unrest and war, is frankly the least of our problems. Our planet will survive, but our civilizations may not, neither will many of the species we see around us right now.
Sadly, we also need to realize that we are just in the beginning of climate change due to the slowness of the systems we are altering. Even if we were to stop emitting CO2 tomorrow morning, the buildup of heat in e.g. oceans combined with the slow melting of ice, will, for example, increase global sea levels with several meters over the coming hundreds of years, almost no matter what we do. In the same way, temperatures will continue to increase with at least another degree globally, even if not another single barrel of oil were to be consumed. But still we continue to use oil. What we are doing now, will have consequences for many millennia.
Where green house gases come from, and how to get rid of them
Green house gases are a bunch of nasty fumes with different warming potential. We mainly talk about Carbon Dioxide, but there are also gases such as Sulfur Hexafluoride that warms Earth about 22000 times more than CO2. Good thing we are not emitting a lot of that. If re-calculated to “carbon dioxide equivalents”, the split of gases globally looks something like the graph below.
Carbon dioxide dominates with about 76%, from burning fossile fuels and cutting down more trees than we plant. Methane is second at 16 %, mainly from livestock, waste land fills and leakages from oil production. Nitrous Oxide represents about 6%, chiefly from fertilizers, and Fluorinated gases makes up the rest, about 2%, from industrial processes.
It probably also makes sense to look at the sources of greenhouse gas emissions in order to prioritize and figure out what to do. Basically, there are five main sources of GHG emissions (yes, we can make this a lot more complicated. Lets not), each with a different pathway to elimination. They split as follows; Electricity, 35%, Agriculture 24%, Industry 21%, Transportation 14%, and Buildings 6%.
Now, to get away with greenhouse gases is not rocket science, really. We simply need to stop using coal, oil and gas. We need to manage additional emissions of greenhouse gases from steelmaking, cement production, livestock and fertilizers. And we need to start removing CO2 from the atmosphere at scale. If we split the reduction by source, the solution is down the line of:
Electricity, heat production, and other energy. The largest sector. We simply cannot use coal and oil to make electricity and heat anymore. And we probably need to massively decrease our energy usage. Luckily, there are alternatives. Solar, wind, hydro and nuclear if you fancy that is the current answer. Yes, it will be a bit tricky with energy storage, base loads, network frequencies and a shortage of skilled labor in various parts of the world. No, that is not an excuse to build more coal plants. Sorry.
Agriculture and Forestry. This might hurt for some, but we can’t eat so much meat. Nothing wrong with a juicy medium rare steak at times, but not as your main source of protein. Half of the mammal biomass on earth are humans. The rest are cows and other red-meat livestock (yeah, there are still some elephants, moose and dolphins out there, but they are becoming more or less a rounding error). Cows fart. Methane. And they eat a lot. We also need to stop de-forestation, and limit the use of Nitrous fertilizers. Oh, and use something else than diesel to power our tractors.
Industry. Some would say we need to consume less. Others that we need to recycle materials much more. Further some that the fossil energy used at industrial sites need to be replaced with carbon neutral energy sources, e.g. biofuels and clean electricity. The answer is probably a combination of all of that. Most agree that the trickiest parts are “natural” emissions from cement production and steelmaking. It is hard to imagine a modern world without concrete and steel. Even with recycling and circular economy, some production is necessary. The answer today is pumping the un-avoidable CO2 fumes underground for permanent storage in e.g. old oil fields (CCS). At least some good use of those. Very expensive, yes. But not much to do about that, is it?
Transportation. Probably the sector with most media attention. And the most obvious answer. We need to stop using oil in our transport system. As easy as that. Electric cars and trucks. Hydrogen powered transport. Bio-fuels for aviation and ships. You name it. Let’s just do it. Now.
Buildings. Fossil energy used to heat buildings, and cook. Please stop. Now. Burn something else than oil/coal in the basement. Connect to a clean electricity grid. Insulate better. Install solar cells on the roof. Do it. Do it now.
Sadly, it is not enough to tackle the emissions themselves. The earth is currently a sinking ship. We need to stop the leak in the hull. We also need to pump out the water. Gas. Current CO2 concentration in the atmosphere is almost 415 ppm, 65 ppm above the (maybe) safe level of 350 ppm. That is a lot of carbon we need to take out of the air. That is why we need to combine the above with Carbon Dioxide Removal at scale.
Why Carbon Dioxide Removal
Carbon Dioxide Removal (CDR) is the only practical and realistic way to prevent the climate on earth from going berserk. Even if the world woke up and realized that we really need to do something about our carbon dioxide emissions (don’t hold your breath, we’re as mentioned still increasing our use of fossil fuels, at an increasing pace), it will simply take too long to replace coal, oil and gas, and make steel and cement production carbon neutral, for the temperatures to be anywhere near where we want them to be. All climate model scenarios presumes carbon dioxide removal (or “negative emissions”) at scale. Obviously, we need to massively reduce, and finally totally eliminate the use of fossil fuels, as well as transform society into a more energy efficient and circular society, re-using natural resources and products to a much higher degree than today, but this will not be enough. Not only because of the simple fact that our societies would completely collapse if we suddenly shut off the supply of coal, oil and gas before plentiful alternatives were available, but also because we are already way above the safe threshold of carbon dioxide in the atmosphere. For millions of years, we have hovered around 200-280 ppm, contributing to the climate we live in today, and now we are reaching 415ppm, increasing. This needs to be brought down to 350 ppm, possibly even lower, in order to stabilize the climate in the long run. That is more than 500 billion tonnes of CO2 that we need to take out of the atmosphere. In addition to the almost 40 billion ton that we add every year. This represents 60 ton of Co2 per human being on earth, plus an additional five ton each year at the current emission rate. Carbon Dioxide Removal is the only way to achieve this. Lets roll up our sleeves. We have a lot of work to do.