Global warming broken down into simple concepts
2011/01/15 § 2 Comments
Recently I wrote about the fact that 97% of expert climatologists (i.e. actively publishing climate scientist) participating in a survey by Doran and Zimmerman agree with the notion that global warming is happening and that humans play an important role in it. However, a large number of people in the general public remain strongly skeptical about it (42% do not think that global warming is a man made phenomenon). Not few reject the concept completely. The reasons for this vary, but I want to attempt to break the seemingly complicated issue down into some basic concepts that are easy to grasp (Eos, Vol. 90, No. 3, 20. Januar 2009).
CO2: The climate factor
Already in the 19th century the Swedish chemist Arrhenius developed the theory that CO2 is an important aspect for explaining the earth’s climate and for the green-house effect, as he called it. Since then the theory has been confirmed repeatedly and it is being recognized that CO2 is one of the most important factors in explaining past climate.
From geological records we know today that in the past climate changes may have repeatedly been caused by changes in the sun’s activity and intensity, or volcanic activity. CO2 apparently always acted as a feedback factor. A warming period was followed by an increase of the atmospheric CO2, which enhanced the warming further.
While the CO2 can act as a positive feedback factor (i.e. a warming factor) of global temperature when being released by natural factors, it has been recognized as having the same effect if released by human activity. And why shouldn’t it?
The climate does not care where the CO2 comes from, it simply reacts to it because the CO2 stops some of the heat coming to the earth’s surface from the sun, from escaping back into the cold space of the universe. Hence the name greenhouse, because it acts similar to the glas of a greenhouse. Hence CO2 can not only act as a positive feedback to natural temperature variations, it can also warm the planet as a reaction to humans releasing it.
How a little bit of CO2 can make all the difference
Some have a hard time understanding that the seemingly tiny amounts of CO2 in our atmosphere can have such pronounced effects. However, in chemistry we know of many examples where little amounts of a chemical have highly noticeable effects. Think of this: if you were to swallow 40 nanogram of botulinum toxin, one of the most poisonous natural substance on the planet, you most likely die. In comparison, a single small sand grain weighs in average 4000 times more. This is a lot of bang for a little bit of almost nothing!
Also think of this counter-intuitive example: the catalyst in your car manages to convert 90% of noxious gases from the combustion into less harmful gases in milliseconds! It does so with only 2 grams of platinum on the surface of the catalyst. The platinum is not destroyed in the process, hence it can do its job constantly during its lifetime for millions of cubic meters of gas.
In chemistry the absolute amount of substances alone is not sufficient to predict the outcome of a reaction. Therefore, our subjective feeling if something will have an effect or not, or how much, most certainly is a bad advisor in predicting chemical reaction outcomes. That is why the science of chemistry exists. If we could judge by our feeling there was no need for it. In the case of CO2 we can claim with confidence that its role is well established and understood as a potent regulator of the earth’s climate.
Past climate as predictor for today
Using different techniques (sediments, trees, ice cores and so on) scientists from different fields have arrived at similar conclusions, i.e. that past climates have been much warmer or much colder at times than todays climate. In some warm times the seas back then must have been teeming with live. BTW, do not equate “teeming with life” as being good conditions for humans!
Interestingly, our oil came into existence because much of the teeming life ended up dead on the sea floor. They had absorbed CO2 and let it sediment when they died. The sedimentations of huge amounts of plant and animal life cleared the atmosphere of large amounts of CO2. Because the dead organisms took the CO2 with them to their grave, the planet could cool down. The simplified equation is: much CO2 equals warm times, little CO2 produces cold times.
If we can accept that science has understood the effect of CO2 correctly for past periods (and everything points in that direction), we must also accept that this effect will act on today’s climate. Therefore: If we put back the CO2 from oil that was produced because of a warm time- as we do today- we therefore recreate the situation that existed back then, i.e. we warm the planet back up. Basically we recreate the situation that existed back then.
As most scientists think, earth back then was an unpleasant place for humans to be.
How we know it really is the CO2‘s fault
As I mentioned above, other factors such as volcanoes, sun activity and others do influence climate. However, it will interest you to learn that climatologist, geologist, astronomers and many other scientists have collaborated to investigate these possibilities. One after another has been ruled out.
Sun activity is actually at a low point right now. In fact, 2005 saw the lowest solar activity in the sun’s 11 year activity cycles, however, 2005 was the warmest year on the 130 year old record (2010 now tied with 2005 as the warmest year). Scientists agree that the sun has played a role in the warming of the past century, however, they also agree that the data shows that CO2 is the main factor since the 1980s.
Aerosols and volcanic activity are actually thought to have a net cooling effect on the global atmosphere. The amount of CO2 from volcanic activity is thought to not be large enough to cause warming because it is counteracted by soot (ash) and sulfate aerosols. In fact, scientists have found that global warming is currently masked by what they termed global dimming! That means, global warming would be even stronger, were it not for pollutants volcanoes and also human activity put in the air, that actually cool the climate (check the video linked above).
Consequences for the planet
What is important to understand is, that obviously life goes on, if it is warm or cold- not necessarily human life though. Because, we know from studying the past that strong changes in the climate have influence what type of life walks the planet. Strong changes often lead to species disappearing and other developing filling niches that occurred when other animals died off.
More extrem weather phenomenas may be a result of global warming, and a quick change between extremely warm years and relatively cooler years. Scientists found strong evidence that climate has what they call tipping points, i.e. points at which negative or positive feedback mechanisms stop the climate from changing very fast. When these tipping points are passed, the feedback breaks down and extremely rapid changes occur, that many creatures and critters would not be able to adapt to that quickly.
This is the case because many plants are adapted to well defined conditions, if they die so do the animals depending on them and so do the animals depending on the animals depending… and so on. You get the picture. In the seas the picture was apparently most dramatic, because warming can lead to large parts of the oceans being rendered unable to support larger organisms because they cary less oxygen when warm.
The problem with warming
The reason why so many people think we should not cause climate changes seem to be mostly two:
1) We do know that our planet does support our life now, but we could run risk that it does not so in the future. For instance could food production suffer severe consequences. Much of the water for farming comes from rivers that are fed by glaciers. If glaciers melt rivers could run low on water or even dry, making efficient farming close to impossible in many regions of the world- if not all.
2) The social consequences are probably even more devastating, when people have to move away from rising water, starvation or desertification for instance.
On a personal note, I am convinced that the effects of global warming and climate change will be extreme and possible dramatic for mankind. However, I don’t mind what you stance is on the consequences. I do not even mind if you personally think that we ought to do nothing about it. I don’t care much for half hearted political acts either.
I just care about the science behind it. The science behind it is solid and clear: global warming is happening and it is human made. This is why 97% of climatologists and the majority of other scientists agree with this statement.
Additional Info: This report from the national academies may interest you
Whether versus climate
A recent article in DN.se emphasizes again, that observing local weather is not representative for the global climate. Last year was one of the coldest in decades in Sweden but the warmest globally for as long as we note temperatures!
Climate danger for civilisation?
A recent article suggests that climate may be a major factor in the rise and demise of civilisations. For instance the romans. Additionally, extreme weather phenomena may become more frequent.
Deniers: In a rather fruitless discussion in the forum below I encountered a typical denier, i.e. a person who does not understand the first thing about the science behind global warming but is eager to disregard any scientific argument. Apparently without ever following one of the provided literature. Contrary to people who I know who are approaching this subject scientifically and who read even the craziest pseudo-scientific attempts to attack the solid science of global warming, these individuals make no effort to ever read anything thoroughly that could contradict their paranoia ridden conspiracy constructs. (–> How to talk to a denier
Interestingly this denier mentioned a so-called Dr. Klaus-Martin Schulte (who is not a real doctor, i.e. a scientist, but just a clinician) who claimed that there is no consensus about climate change and global warming. This text was so preposterous that I can really not have it posted here. It is intellectual turd: Teeming with nonlogical arguments, quite likely purposely false claims and lies, or at the least scientific incorrectness based in ignorance and incompetence. However, you are free to google it for yourself of course. It is being rebuked and rebutted perfectly here: