Disclaimer: This topic requires a highly balanced and sophisticated discussion, and I have done my best to do this. I am happy to concede my view point given compelling evidence to the contrary. Confirmation bias and bad sampling is capable of causing serious distortions. I am writing this blog post mostly to talk to my friends, because most people have a hear say understanding of this topic. Also note the numbers I quote are debated. I’ve have also used my judgement to remove what I considered to be unreasonable arguments.
First I would like to correct my previous statement about mass extinctions in Earth's history. Events causing mass extinctions have accompanied large changes in CO2 levels and Temperature. It by no means implies causation. There are documented events where large changes over 10000-20000 years in CO2 levels have left life relatively unharmed, it simply moved pole ward.
Despite the fact that the media likes to call it settled science there are ongoing debates. There are doubts cast about the magnitude of the effect and its use in policy making. It may well be the greatest scientific scandal of our generation. There is enough evidence to suggest that the group in charge of this discussion will suppress information that can be treated as contrary to their political agenda. However, there is an iota of truth, which is that CO2 is a green house gas. It therefore stands by reason to demand the replacement of Al-Gore and friends with a group that is capable of a balanced discussion. When that is done we may arrive at vastly different conclusions. (Seach Al Gore plagiarizes clip from Hollywood movie)
This discussion and the previous one must be viewed in the context of this comment made by Lubos.
"There wouldn't be any significant strain anywhere if a 10 deg C of warming were divided to 300 long years. It's just damn 0.03 deg C per year. No one can notice it. One needs a very long term memory to see this slow change. For all practical purposes, the rate of change is zero. Every point of this process is clearly compatible with all major life forms and business that exist. So any concern is self-evidently irrational."
You can contrast this with what I had stated in my previous blog post. I considered deleting it but I decided to preserve the paranoia of a generation intact.
"I understand his key point that one weather pattern is as good as another, but that is not all that there is to this discussion. Ecosystems take a long time to build and adapt to existing weather patterns."
Notice the word memory that is central to this discussion.
My blog post must also be seen in the context of another statement where Lubos said it is nothing scary if earth warms by 5 degrees this century, in the context of high sensitivity and high emissions. To convince me of this he would need produce a peer reviewed report and covering all important topics in a balanced manner. I am not denying that one such argument could exist, it certainly intrigues me.
Review of Climate physics
I will review some basic facts and uncertainties.
There are documented events in Earth's history where changes of 8 degrees or more of warming was recorded in periods of about 10,000-20000 years. There are times in history when Palm trees were found in the Arctic and Antarctica were mostly Ice free and life on earth was flourishing. There are periodic glacial cycles happening in the time scales of 100000 years.
The warming trend we have seen in recent history is within the range of natural variability. Wind and Ocean movements along with topographical variations largely determine local weather. Changes in ocean and wind circulation will appear as large changes locally.
CO2 is a green house gas. And it is accepted that it will cause warming. A controversial is the number called climate sensitivity of temperature to CO2. Sensitivity of temperature to CO2 is logarithmic. From laboratory measurements it has been shown that CO2 will cause a 1.1 degree warming per doubling in concentration. The feedback effects such as water vapour, cloud cover and albedo changes are debated.
CO2 levels have increased from 280 PPM to 400 PPM since the industrial era and most of it happened this century. We are increasing at rate of about 2-3 PPM per year. The earth has warmed a total of 0.8 degrees during this period. The current warming shows a trend of 0.1-0.15 degrees over a decade. It is generally accepted that the models run too hot and this is the most serious criticism.
Just from this number alone a sensitivity of about .8/log2(400/280) gives 1.5 per doubling of CO2. This is certainly not a good way to calculate things, it is just to give you an idea. When one studies Climate sensitivity there are 2 relevant numbers, first is Transient Climate sensitivity (TCS) and Equilibrium Climate Sensitivity(ECS). The first is relevant for shorter timescales, the second is for longer timescales.
Intergovernmental Panel on Climate change (IPCC) which is basically a big compilation of papers suggests that ECS has a range of 1.5-4.5 with a best guess estimate of 3. The IPCC was formed to reflect the best understanding of the scientific community. Some express doubts about its true motives. Judith Curry, a skeptic who in my opinion provides balanced discussions, estimates Transient climate sensitivity at 1.3K.(.9-2.5 90pc confidence interval) roughly similar to IPCC estimates of 1-3. Judith Curry estimates Equilibrium sensitivity at 1.74 (1.1 – 4.5 at 95pc confidence interval). IPCC makes an estimate of 3(1.5-4.5). Notice the large uncertainties in both estimates. The tropics would warm about half as much and poles would warm twice as much.
IPCC makes a case that 450 PPM is the most we should aim for otherwise we will experience a catastrophic climate destabilization. The 450 PPM limit requires the deployment of a short term response as it is 20 years from now. There are people who think that 600 PPM can be considered safe, which requires a long term response. Lubos considers everything to be safe, which requires no response.
The Meaning of a Degree.
The capacity of life forms to adapt to changes in climate is governed by their capacity to move and find their natural habitats. I will do to an intuitive calculation where I will ignore changes in rainfall.
Considering a summer temperature on the poles at -10 degree, and equatorial temperatures of 50 degrees and 10000 kms is the distance between equator to the poles, I got number of about 160KM/degree. I am not sure if this number is correct as literature is all over the place. This number is smaller at the equator and larger at the poles, and smaller if one goes up the altitude.
So for a 3 degree warming scenario this century would correspond to about 500 kms. I don’t have clear numbers on how quickly life can move to adapt, it’s certainly easy for fishes and elephants. We should consider the slowest moving aspects of the ecosystem.
There is evidence that terrestrial life given space is well poised to keep up with the current pace of current warming. Some species would lag behind and my impression is they are exceptions. We can help them make these movements and people are already on the job. I have left this investigation midway, due to lack of clear information.
The Island effect and practical considerations
We have isolated forests in biodiversity hotspots. This is a side effect of interconnected road networks. The health of the species in ecosystems is related to its interconnectivity. In general climate change happens and is inevitable. Irrespective of the specific CO2 issue, it is a good idea to maintain wildlife corridors allowing free passage between ecosystems. Small changes can be absorbed into tolerance ranges. With restricted mobility, most species are in the mercy of their tolerance ranges or human intervention.
Also to add to this there are real islands and other isolated ecosystems such as mountain tops, mangroves etc. In specific depending on where you live a degree corresponds to about 150 meters in altitude. This number is smaller near the equator and larger closer to the poles. Small range shifts happen all the time and they have been observed consistent with some warming. But a large one can wipe out entire ecosystems.
Lubos for suggested that we can rescue the polar bears, when the Arctic ice melts, and they will probably do fine in North Canada or Greenland. There are millions of species from fungi to mammals on earth and I think it is silly to think humans can handle every aspect of it. It is important to give enough space for other species to co-evolve, preferably in their natural habitats.
Coral are important because they form a foundation for food webs in the ocean. They are not the only organisms that can be regarded as founding stones, phytoplanktons are also important in that regard.
Coral sensitivity to temperatures cannot be ignored. It is generally understood by the community that they thrive in a narrow band of temperature ranges and are sensitive to environmental conditions. Corals are certainly growing, capable of making range shifts and transport to new places. The time scales involved for corals to regrow is 10-20 years. (Search Isolated Coral Reefs Can Heal Themselves)
Conservative estimates suggest that a further warming of 1 degree is dangerous for most reefs that currently exist. There is evidence that corals adapted to warmer temperatures(Holocene), by establishing new ranges, however to my knowledge it is not clear that corals are capable of making range shifts fast enough. There is some evidence that they are making these range shifts. Long distance migrations are rare events, I don’t have statistics on what is considered rare.(Search Is the great barrier reef moving to Tasmania?)
To my best understanding coral research is at its infancy. In the last decade itself a lot of new things were discovered. Corals may hold many surprises they have been around for 200 million years and have seen many changes. At the face of it appears that a degree is too much for them. Extrapolating based on short term trends may not lead to the correct assessment. It is possible that the reefs are learning about their new environments. There must be an objective way to assess the situation. (Search Peter Ridd Don’t Trust the alarmists). (Also read https://judithcurry.com/2016/05/24/coral-bleaching-debate/)
It is true that the coral reefs are overall in a very bad shape. We should address the other major and local factors leading to decline of coral reefs which is rather significant in my understanding. To my knowledge reefs isolated from human impacts are able to cope with warmer weather. There is hope, atleast from what I read, that corals can learn, to adapt to a moderately warmer world with more CO2. There is little hope that they can deal with others impacts due to humans. There is a strong correlation between human activity at local level and coral health.
Acidification of the oceans
Lubos said that no marine animals can see such small changes in ocean pH. The skeptics like to call it neutralization.
The ocean Ph has changed by .1 ph consistent from 8.2-8.1. Loosely consistent with an expectation of log10(400/280) = .15. Large carbon emissions scenario suggests a pH drop of .3-.4. Consistent with log10(1000/400) = .4. There are theories about buffering effect which I am not in a position to verify. Buffering is something that can delay things in my understanding.
The best way to do such a study is through lab experiments in controlled conditions, which is what many researchers are studying. Adaption is an important consideration. These experiments are usually short term experiments so by definition they ignore possibilities of adaption. There is evidence for adaption in short timescales.
To my best knowledge there are no known species where acidification is a direct existential threat. How they fare in a competitive environment like the biosphere is not known. There certainly exist a whole bunch of species, which don't see acidification or have positive effects.
To illustrate the effects I want to highlight one study which is an extreme example.(Closer to 2000PPM). In this experiment they grew corals(a class called hard corals) at environment about .7 pH lower than normal, it has been noticed that Calcification rates drop to zero and the skeletons completely dissolve. The most interesting part is that the corals don’t die, upon subjecting to normal conditions they completely recover.
Experiments from volcanic vents (Bubbling CO2 in the ocean) show the effects of acidification. Corals and calcifying species are among the most seriously affected, sea grasses are favoured. Generally most lab experiments tend to agree that by 1000PPM we will see sharp changes to ocean bio-chemistry.
Some argue that it will be beneficial to the ocean overall, However I am not entirely convinced. (See https://judithcurry.com/2015/09/23/ocean-acidification-discussion-thread-2/)
Some like it warm.
There are people who think that a 1-2 degree warmer world would come with it benefits and make fair arguments. There are documented benefits to plant growth and farming. We are currently in a CO2 famine in geological timescales. A warmer world is a wetter world. And rain is usually a good thing. They do exist in the context of this century. There also exist biological and ocean stabilizing factors, and eventually the CO2 will mix into the deep ocean and stabilize.(~few thousand years). Some even suggest conspiracy theories like controlling the world using energy and solar lobby groups.
The wrong reasons to worry about climate change
I think the most serious considerations are ecological. Human beings with proper management are highly capable and efficient. If humans are the only concern, the obvious benefits of cheap energy are evident. Many would disagree with me.
In this article New York Times suggests that, kids in Africa are dying because of climate change and Trump not following the Climate Pledges will kill more of them. (Search As Donald Trump Denies Climate Change, These Kids Die of It). We should be looking to directly help drought prone regions instead of blaming it on CO2. Any direct help by building desalination plants etc, is meaningful. Cutting CO2 emissions is useless. If we need to fire up a coal powered plant because it is the easiest way, we should not hesitate one bit to do it. Paranoia about each natural event is not justifiable. The discussions in the media have turned into a sudden interest in weather.
Some regions will be affected disproportionately from climate change, and some will benefit (Search Sahara Greening). With proper management we can handle it. Droughts are an exception rather than a norm because of increased overall precipitation. We can certainly look at hydroponics, if the situation ever gets too serious. Lubos makes a case that change in local weather patterns will be an exception rather than the norm because they follow local gradients.
1 meter sea level rise is expected this century and will continue to rise for coming centuries. We can solve it will be slow and predictable enough to move, and we have technologies to deal with it. We won’t be sitting ducks when the water rises. If the Greenland ice melts we have an entire region now suitable for inhabitation that certainly must count for something. Migration may look scary but people do it all the time.
Careful management of ecosystems and rehabilitation of endangered species would be needed. My impression is that this would be an exception rather than a norm. People are monitoring vital signs very closely which is a good thing.
An organized defence of the IPCC
An organized defence and well funded of the IPCC must be demanded. It will accelerate this discussion rapidly. A good scientific argument would stand up to scrutiny. Surely they must not be afraid to conduct a defence. This is highly relevant because 450 PPM is 20 years from now and any rapid change in energy policies would destroy economic growth and lifestyles. IPCC has an intrinsic bias towards alarming papers.
This defence can be done one step at a time starting with 600PPM compared to 450 PPM. It will be a while before we reach 600 PPM. We can study the vital signs, and revaluate at 500 PPM. If 1000PPM looks bad, it does not imply that 450 ppm will necessarily lead us to right conclusions.
Energy considerations: Alarmed vs Prepared
Lubos said that we will cripple human technological growth, if fossil fuels are taxed heavily. Even if they are taxed heavily because of lack of compelling alternatives people would still use them, so basically it’s useless. One thought that echoes though the community is that we are basically doing nothing with the green energy plan. This program is changing temperatures by a fraction of a degree by the end of this century and costing trillions in subsidies. (See Paris Agreement won’t change the Climate)
It would be right to say that we have adopted a panic solution. There are some situations which demand a panic response. Many people think that this is not one of them, these people must be given a fair voice.
While Lubos would disagree, I think there is a case that we should be looking to move towards hydrogen based fuel economy or something similar and burning all the fossil fuel reserves may not be a good idea. Cutting global emissions right now is not as meaningful as a well researched deployment of a long term solution. There are compelling technologies that exist which need development, my favourite one is accelerator driven subcritical reactor to burn thorium. It makes sense in the Indian context. Fusion may be closer than ever. (See Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte)
800 PPM and beyond
The most interesting aspect about Lubos Motl viewpoint, which sharply differs from others who study this subject is he looks a coarse grained picture. It is justifiable. If it does not favour one life form then it would favour another. Higher CO2 levels would favour Photosynthetic organisms. CO2 is an essential ingredient for life and we are carbon based life forms. He also thinks that we should not be afraid of uncertainties and not all changes are bad.
Certainly our views tend to diverge in the long term. It is a very different kind of intelligence and must be given due consideration. I don’t have the expertise required to evaluate him. I tend to think that he overestimates the capacity, extent and timescales required for organisms to adapt, however I could be wrong. One of us is doing science fiction and I honestly cannot tell who is. After evaluation, I tend to agree with him on shorter timescales.
As I reviewed this subject I realize that it is hardly reasonable for an ordinary person to study such a vast subject. Most people would want a simple answer to such a complex question and move on with other aspects of life.
I cannot effectively conclude such a complex question. However I must indicate that there is suppression of scientific viewpoint, which ends up dividing people politically. An organized defense of IPCC is a start. I highly recommend Judith Curry’s blog, to find a balanced contrarian viewpoint, contrasted with other blogs. It is unfortunate that she had been labelled a climate heretic, for asking seemingly obvious questions.
If you need evidence that the people incharge are not very good, I will highlight a quote from Stephen Schneider, who has been pivotal in this movement.
“On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we'd like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broadbased support, to capture the public's imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This 'double ethical bind' we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both.”
My viewpoint currently is we can wait for the engineers figure out compelling energy alternatives. It is necessary to develop these technologies. Making small emission cuts now is meaningless. I think sooner is better has credible reasoning, but there is no need to panic and don’t believe the scariest stories you hear.
I think a good way to end this discussion is a quote from Jennifer Smith, coral researcher. “I can’t tell you what the outcome is, because we’re still in the middle of it,” (Search Remote reefs thrive despite climate change)