Scientist Skeptical Of Climate Skeptic.

[Essay]

Climate change skeptics challenged

 

Fred Singer (accompanied by Dr. Wm. Gray) spoke at our local university recently. Prof. Dr. Scott Denning, described as a top ten carbon-cycle expert, was in the audience and is now posting in the comments section of our local newspaper. Some of the denialists are trying to take him on, but he is sticking to the science and explaining things masterfully....

 

 

http://www.coloradoan.com/article/20110719/NEWS01/107190333/Skepticism-Controversial-speaker-Fred-Singer-says-global-warming-climate-science-bunk-

 

“You don’t vote in science,” Singer said, criticizing peer review.

 

CSU atmospheric science professor Scott Denning interrupted, saying he’s skeptical and needs a high degree of evidence to believe a claim that runs contrary to common sense.

 

“So, you know, you don’t really think humans cause climate change; we think heat causes climate change,” he said. “We know that burning fossil fuel produces CO2, we know that CO2 emits heat. Now most people know that heat warms things up.”

 

He said Gray admitted that the Earth has seen a small increase in carbon dioxide levels in recent decades, but if China and India power their growth with coal, carbon levels will increase significantly.

 

“You hypothesize that something’s going to come and get rid of all that heat,” he told Gray and Singer, “but you haven’t told us what it is that’s going to get rid of that heat or why you believe it’s going to get rid of all that heat, and I would suggest that people be pretty skeptical of that claim. Why should we believe you?”

 

“Scientists should all be skeptical,” Singer said.

Well Fred, that was a snappy comeback, eh?

 

 

For comments on the follow up article:

http://www.coloradoan.com/comments/article/20110721/NEWS01/107210341/Climate-change-skeptics-challenged

 

For comments on the original article:

http://www.coloradoan.com/comments/article/20110719/NEWS01/107190333/Skepticism-Controversial-speaker-Fred-Singer-says-global-warming-climate-science-bunk-

 

Dr. Denning is posting on both, but be sure not to miss the links for "replies" that are follow-ups, or additional comments specific to the post, (at the bottom of some posts) which only display when clicked.

 

===

 

The real point, as I tried in vain to get Fred Singer to address, is that CO2 emits heat (measured), and that heat warms things up (measured). Climate sensitivity is quantitatively shown by the Little Ice Age, the Medieval Warm Period, and (especially) the Pleistocene Ice Ages.

 

Consensus? Who cares! Common sense? You bet!

-Scott D.

 

Without the heat radiated downward from greenhouse gases in our atmosphere, the Earth's surface temperature would plummet by hundreds of degrees every night, just like on the Moon. The Earth's surface receives nearly twice as much heat radiation from atmospheric greenhouse gases as it absorbs from the Sun. This is not a matter of opinion, but can easily be measured by instruments.

-Scott D.

 

Thank you Dr. Denning

 

~

[C1ay]

C1ayton has added his comment there :)

[Qfwfq]

Those discussions are no longer available.

[Universal Student]

Since water vapor comprises about 95% of the “greenhouse gasses”, and since methane has a GWP 72 times that of carbon dioxide, focusing so much more emphasis on only carbon dioxide is rather myopic.

[JMJones0424]

Since water vapor comprises about 95% of the “greenhouse gasses”, and since methane has a GWP 72 times that of carbon dioxide, focusing so much more emphasis on only carbon dioxide is rather myopic.

 

OK, I'll bite. How do you propose we dehydrate the atmosphere? What do you propose is a better way to manage AGW? Or, as is more likely, are you a hit and run troll that regurgitates sound bites without bothering to fully consider the situation?

[Universal Student]

Thanks for the friendly welcome.

 

It is possible that I have been studying climate change since before you were just a gleam. There are many factors involved in climate change and climate stabilization, lots of feedback loops, and other interactions that seem to be ignored.

 

IMO it was disingenuous to suggest dehydrating the atmosphere. The comparison was to emphasize relative contribution between different atmospheric gasses. There are tables available which list the estimated GWP of various gasses.

 

What do you propose is a better way to manage AGW?

Rather a loaded question, isn’t it? It presumes, not only that global warming should be managed, but also that it can be managed. There are two aspects to consider. First, that global warming is continuing, and second, that it is increasing in rate. IMO, even if we threw the economic weight of the world’s governments at the situation, the best we might be able to do is decrease or stop the rate of global warming increase. I seriously doubt that we can stop the increase in global warming.

[JMJones0424]

It is possible that I have been studying climate change since before you were just a gleam.

And it's possible that you haven't. Either way, the length of time you have studied a subject does not directly support your position.

 

If I understand you correctly, your position in fact is not that focusing on CO₂ is myopic, but rather that AGW is in question, and that even if AGW is occurring, our ability to manage the effects is limited. If this is correct, then may I suggest you start a thread making your case with sources. Unsupported opinions are of little value. It makes little difference to me what some anonymous person on the internet seriously doubts.

[Universal Student]

And it's possible that you haven't. Either way, the length of time you have studied a subject does not directly support your position.

The comment was intended to indicate ongoing involvement in the issue, as opposed to knee jerk reactions or popular opinion.

 

If I understand you correctly, your position in fact is not that focusing on CO₂ is myopic, but rather that AGW is in question, and that even if AGW is occurring, our ability to manage the effects is limited.

That is incorrect. Your comments indicate that you see what you wish to see, not what is there.

 

Unsupported opinions are of little value. It makes little difference to me what some anonymous person on the internet seriously doubts.

Inevitably, comments on virtually any subject are opinions, either our own, or those of someone else. Links to the opinions of “experts” can be found on both sides of the issue, which results in credibility being simply a matter of who you choose to believe.

If comments are not welcome here unless agree with the opinions of the majority of members, let me know and I won’t bother to share information I have gathered over the years.

[Universal Student]

What is interesting about the OP, and about Scott Denning’s comments, is that both seem to insinuate that all AGW skeptics believe that there is either no global warming, or that if there is, it is not being caused by mankind. I have seen very few that would fit into either of those categories. Rather, most skeptics seem to lean towards relative contributions to climate change by various factors, cyclic changes, and extremely complex self-correcting feedback.

[Essay]

What is interesting about the OP, and about Scott Denning’s comments, is that both seem to insinuate that all AGW skeptics believe that there is either no global warming, or that if there is, it is not being caused by mankind. I have seen very few that would fit into either of those categories. Rather, most skeptics seem to lean towards relative contributions to climate change by various factors, cyclic changes, and extremely complex self-correcting feedback.

If "most skeptics" have refined their positions, that is nice; but it doesn't change the physics of our atmosphere. It is specifically the "relative contribution" that is the problem.

 

 

I think Dr. Denning's concern is about the future, and the effect that the CO2 forcing will have on the climate over the long term. It is roughly calculated to be between 5 and 10 times as severe as the change between LIA conditions and MWP conditions, over then next few centuries.

 

Current "climate change" is fairly anecdotal, and doesn't much figure into these concerns about the drastic change we have foisted upon the (relative) chemical equilibrium of our atmosphere (and the coupled atmosphere-ocean system too, re: acidification of the planet's food chain).

 

Soon, CO2 levels will approach those not seen since the end of the Miocene, over 5 million years ago--before our species and greater biodiversity arose--when the megafauna still dominated. As the climate and environment adjust to the changes, I'm skeptical that the ecosystem services--upon which civilization relies--will not be disrupted faster than we can cope.

 

This anthropogenic change in CO2 concentration (as well as other GHG's) is an order of magnitude greater in strength than the other ("various factors") forcers; and it is occuring more than an order of magnitude faster than those other forcers, which normally operate on some geologic time scale rather than a generational time scale. That is the "relative contribution" you need to consider and judge.

 

And unlike the "natural" forcers, anthropogenic forcing is 24/7/365, decade after decade, for the coming centuries ...and the coming generations of civilizations attempting to hang on...

 

...through changes much greater and faster than those between the LIA & MWP!

(...which were puny compared to what climate normally can do over geologic time.)

===

 

We've begun to see the first hints of these more drastic changes to come....

 

Hence, the skepticism over claims that there is nothing to worry about or change.

 

...especially for the eyes of our children's grandchildren. What planet will they see?

 

~ :blink:

 

p.s. I've got a call in to the newspaper to see if those OP links are still available somewhere else.

[Universal Student]

IMO, a few skeptics have refined their positions, but most have been misquoted or misrepresented. Someone might say, “I haven’t seen convincing evidence yet of the exact cause…”, and the response might be, “So you don’t believe mankind is causing global warming.”

 

I am also concerned about the future. Part of the problem might be in the inaccuracy of our education system and the sloppiness of past “experts”. You may remember seeing graphic representations of the Earth, where the Earth is represented by a 4 inch circle, and the atmosphere is represented by a 6 inch circle. That sets the impression in young minds that there is a huge atmosphere surrounding the Earth. Here is an example they should have used.

Earth = 8000 miles diameter

All of the weather occurs within the first 7 miles.

90% of the atmosphere is contained within the first 50 miles.

 

Basketball = 9 inches in diameter

All of the weather occurs within the first .0078 inches above basketball

90% of the atmosphere is contained within the first .05625 inches above basketball

STS LEO = 186 miles = .21 inch above basketball

Orbit of 240 miles (ISS) = .27 inch above basketball

 

Remember that virtually all of the oxygen in the atmosphere was created by plants, which also dramatically reduced the CO₂ content. Plants love CO₂ and flourish well in moderately high concentrations. That is one of the self-correcting feedback systems, and is why maintaining our forests is so important.

 

I disagree that the anthropogenic change in CO₂ is greater than all the other factors. It is one of many factors.

 

One thing seems clear to me, and that is something I mentioned previously. Let’s say that we managed to stop the increase in CO₂ production per person. The growing population would still contribute to an increase in overall CO₂ production. Let’s say we manage to level off the production of CO₂, so that it doesn’t increase even though the population does. That still leaves us releasing huge amounts of CO₂ into the atmosphere. Even if we managed to decrease CO₂ production planet wide, we would STILL be releasing huge amounts of CO₂ into the atmosphere.

 

What would happen if all of mankind stopped producing CO₂ altogether? Would that solve the problem, or would it still be with us?

[Essay]

IMO, a few skeptics have refined their positions, but most have been misquoted or misrepresented. Someone might say, “I haven’t seen convincing evidence yet of the exact cause…”, and the response might be, “So you don’t believe mankind is causing global warming.”

 

I am also concerned about the future. Part of the problem might be in the inaccuracy of our education system and the sloppiness of past “experts”. You may remember seeing graphic representations of the Earth, where the Earth is represented by a 4 inch circle, and the atmosphere is represented by a 6 inch circle. That sets the impression in young minds that there is a huge atmosphere surrounding the Earth. Here is an example they should have used.

Earth = 8000 miles diameter

All of the weather occurs within the first 7 miles.

90% of the atmosphere is contained within the first 50 miles.

 

Basketball = 9 inches in diameter

All of the weather occurs within the first .0078 inches above basketball

90% of the atmosphere is contained within the first .05625 inches above basketball

STS LEO = 186 miles = .21 inch above basketball

Orbit of 240 miles (ISS) = .27 inch above basketball

 

Remember that virtually all of the oxygen in the atmosphere was created by plants, which also dramatically reduced the CO₂ content. Plants love CO₂ and flourish well in moderately high concentrations. That is one of the self-correcting feedback systems, and is why maintaining our forests is so important.

...yep, we know; this is a science forum.

 

I disagree that the anthropogenic change in CO₂ is greater than all the other factors. It is one of many factors.

 

One thing seems clear to me, and that is something I mentioned previously. Let’s say that we managed to stop the increase in CO₂ production per person. The growing population would still contribute to an increase in overall CO₂ production. Let’s say we manage to level off the production of CO₂, so that it doesn’t increase even though the population does. That still leaves us releasing huge amounts of CO₂ into the atmosphere. Even if we managed to decrease CO₂ production planet wide, we would STILL be releasing huge amounts of CO₂ into the atmosphere.

 

What would happen if all of mankind stopped producing CO₂ altogether? Would that solve the problem, or would it still be with us?

...regardless of the climate, what about the ocean chemistry!? ;) But regardless....

 

 

Saying that CO2 "is one of many factors" does not preclude it from becoming an overpowering factor. The sun could also become an overpowering factor, but it has been relatively stable over geologic time, changing very gradually. Volcanoes could overwhelm the other factors, but that hasn't happened for eons, on anything but a very short-term and hemispheric scale. A meteor hit around 4.5 kya seems to have changed the global climate for decades or even a whole century. But CO2 (and consequent greenhouse effect) is currently increasing in magnitude enough to overwhelm the other natural forcers that combine to produce our climate.

 

The changes in forcers which brought on the LIA & MWP (little ice age & medieval warm period) are very small (by about 10 times) compared with the change in forcing that moves us from ice age into interglacial conditions and back.

 

The current change in CO2 is shaping up to be as large as that past ice age forcing, but in the opposite direction. We are talking Miocene conditions here. It is already as large as the forcings of the MWP; but it has not been operating for nearly as long, so its effects are not yet fully manifested (plus it began from a different starting point). Though the ITCZ has recently moved as far north as it ever was during the MWP, so we are starting to catch up.

===

 

Why do you "disagree that the anthropogenic change in CO2 is greater than all the other factors?" The figures are availble to look at.

The forcing of the MWP was about 0.5W/m^2 for decades or even more than a century.

 

What do you think 4 W/m^2, from doubling CO2, will do after a century or two...

...and that is 24/7/365 over the whole surface; unlike the cause of ice ages, which is simply a waxing-n-waning, 7 W/m^2, redistribution (persisting over centuries) of the same incoming wattage.

===

 

But I don't want to argue complexities, data, and details.

 

I would like to point out that your concerns about how we can cut CO2 have an answer!

 

The "Wedges" strategy:

 

http://cmi.princeton.edu/wedges/pdfs/teachers_guide.pdf

 

http://cmi.princeton.edu/wedges/

To get on track to avoiding dramatic climate change, the world must avoid emitting about 200 billion tons of carbon, or eight 25 billion ton wedges, over the next 50 years.

 

 

We Have the Technology

Each of the 15 strategies below has the potential to reduce global carbon emissions by at least 1 billion tons per year by 2060, or 1 wedge. A combination of strategies will be needed to build the eight wedges of the stabilization triangle.

see website for list of 15 strategies such as doubling fuel efficiency for 2 billion cars, substituting natural gas for coal, ramping up solar and wind by many times, changing land-use practices, etc.

 

AND

 

That last one [land-use changes] can even draw down excess carbon from the atmosphere, if we get the other strategies to cut increases and stabilize concentrations.

 

Those needed land-use changes also help alleviate poverty and improve resilience to pending climate change. These land-use changes can help address many of the 8 millennium development goals, i.e.,

http://www.worldwatch.org/files/pdf/Mitigating%20Climate%20Change%20Through%20Food%20and%20Land%20Use.pdf

see page 33, first paragraph re: goals 1, 3, and 7.

...and that's just a partial list. I could go into more detail on the co-benefits of land-use change if you're interested.

===

 

There are now 16 identified strategies, and we only need to pick 8 (or a combination of all 16) depending on what works best for a given region, etc.

 

So we could intentionally manage the carbon balance in our atmosphere, instead of unintentionally (and very quickly) changing the slowly evolved, and critical balance.

 

~ :)

[CraigD]

If comments are not welcome here unless agree with the opinions of the majority of members, let me know and I won’t bother to share information I have gathered over the years.

Hypography is a site website for the discussion of – sharing information and ideas about – science by people from many different educational and life experience backgrounds. Every member is expected to read and follow our forum rules, which may be read via the preceding link or a link that appears near the top of every page.

 

Although there’s no rule requiring you to agree with the majority of members, there is an important one stating “in general, back up your claims by using links or references.” Though it’s almost always possible to find online references supporting almost any claim, those supporting incredible claims tend to be quickly pointed out, so this rule tends to make us agree on a large body of data and theory I’d term the “scientific consensus”. As this consensus is ever changing, there no shortage of differences in speculative opinions, despite broad agreement about most of it.

 

We welcome your opinions and ideas, but only if you back up the claims they contain. As has been pointed out upthread, just asserting that you’ve spent years gathering them doesn’t satisfy this requirement.

 

Inevitably, comments on virtually any subject are opinions, either our own, or those of someone else. Links to the opinions of “experts” can be found on both sides of the issue, which results in credibility being simply a matter of who you choose to believe.

The claim that many climate scientists disagree that the amount of carbon in the form of greenhouse gasses in the atmosphere is increasing, driving a rise in total heat, and that this increase is driven primarily by an increase in human-caused carbon emissions, is wrong. See wikipedia articles climate change denial and list of scientists opposing the mainstream scientific assessment of global warming

 

I disagree that the anthropogenic change in CO₂ is greater than all the other factors. It is one of many factors.

It’s certainly true that human-caused CO₂ and other carbon-containing gas emissions is only one, and at about 5%, far from the largest, source of carbon emissions, it is the great rate at which this carbon emission source is increasing, and unless technical solutions are implemented to reduce it, likely to continue to increase, which makes it so significant. (sources: wikipedia articles carbon cycle and human impact on the environment

 

One thing seems clear to me, and that is something I mentioned previously. Let’s say that we managed to stop the increase in CO₂ production per person. The growing population would still contribute to an increase in overall CO₂ production. Let’s say we manage to level off the production of CO₂, so that it doesn’t increase even though the population does. That still leaves us releasing huge amounts of CO₂ into the atmosphere. Even if we managed to decrease CO₂ production planet wide, we would STILL be releasing huge amounts of CO₂ into the atmosphere.

UniStu, research this a bit, replacing phrases like “huge amounts” with actual numeric estimates, not only for the emission of carbon purely due to human bodies, but its intake. I believe you’ll discover that humans and other plants and animals are essentially carbon neutral, absorbing as much as they emit.

 

What would happen if all of mankind stopped producing CO₂ altogether? Would that solve the problem, or would it still be with us?

As Essay discussed in this post, yes, if humans stopped producing CO₂ altogether, best climate models show that the average global temperature would stop rising, and resume the decrease that began about 5,500 years ago, and is projected to continue decreasing for about 50,000 years, until the next glacial period. (sources: wikipedia articles Holocene and glacial period)

[Universal Student]

Thank you for the balanced, educated, insightful, and civil response. You clearly have done your homework. I actually agree with most of what you posted. I am a little more pessimistic and skeptical than you.

...yep, we know; this is a science forum.

Even science forums have lurkers (and members) who don’t have all the information. Yet.

 

...regardless of the climate, what about the ocean chemistry!? ;) But regardless....

The ocean is a major force controlling climate. The chemistry determines both diversity and proliferation of aquatic life, which in turn determines the amount of carbon sink and oxygen production. But then you know this, since this is a science forum. :)

 

That last one [land-use changes] can even draw down excess carbon from the atmosphere, if we get the other strategies to cut increases and stabilize concentrations.

An often overlooked aspect of this is the production of CO₂ by growing rice. Rice is a staple food for billions of people, yet most rice production results in large amounts of CO₂ emissions. Some estimates indicate that rice produces as much as 24 times the carbon as beef, per pound consumed.

 

I never intended to get into a deep discussion on this subject, which is a little outside my expertise. I originally only intended to mention the major role of water vapor in the “greenhouse” effect.

[Essay]

I never intended to get into a deep discussion on this subject, which is a little outside my expertise. I originally only intended to mention the major role of water vapor in the “greenhouse” effect.

...well, it's always worthwhile--and enjoyable--to look more deeply.

 

 

But to address your points from above....

 

 

 

Yes, "chemistry determines both diversity and proliferation of aquatic life," and so changing it rapidly--as shown in the geological record--causes extinction events. We need to avoid that.

That point about chemistry applies to terrestrial life also. The atmosphere participates in a dynamic chemical equilibrium with the ocean, and with the terrestrial soils also.

===

 

&

Yes, lots of methane comes from rice production. Perhaps that is why the cover photo, from that "Worldwatch.pdf" link I provided above, "Mitigating Climate Change through Food and Land Use," features terraces of ripening rice. Did you notice the first three sentences?

 

"Land makes up a quarter of Earth's surface, and its soil and plants hold three times as much carbon as the atmosphere. More than 30 percent of all greenhouse emissions arise from the land use sector. Thus no strategy for mitigating global climate change can be complete or successful without reducing emissions from agriculture, forestry, and other land uses."

http://www.worldwatch.org/files/pdf/Mitigating%20Climate%20Change%20Through%20Food%20and%20Land%20Use.pdf

===

 

&...

Water vapor? Oh, that was your first post, wasn't it; I suppose as a way to highlight Dr. Denning's focus on CO2? But....

 

Water vapor (as the "dehydration" comment was designed to suggest) is not something we can control. It changes daily in response to heating (and then affects climate as a GHG also), but water vapor is always just a part of the average baseline upon which other forcers act over the long term. Water vapor is not an independant forcer, in the way that solar output or volcanoes are; but it dependantly affects climate as a part of those "extremely complex" feedbacks you mentioned.

 

And, by the way, "extremely complex" feedbacks are not necessarily "self correcting" as you wrote. There are both positive & negative (amplifying & damping) feedbacks; but overall, from a Gaia perspective, it seems our very complex system has always eventually evolved into a fairly basic pattern for self regulation. Though history shows us how easliy that "self regulation" can be disrupted.

History also shows us that it takes millennia to recover from any but the most transient and local disruptions; hence the concern over this pending, relatively significant, long-term and global, disruption to our relatively stable atmospheric (and oceanic) chemistry.

===

 

But about methane also, as you mentioned, being a more potent GHG. Yes, but....

It is important to consider the total amount of methane; and since it is so much less than CO2, it doesn't affect climate nearly as much as CO2 does currently. Nor does it acidify the ocean as excess CO2 is doing. Nor does it last as long in the atmosphere as CO2 does. So overall, CO2 is much more of a problem; hence the focus.

 

Sure, methane is a problem, especially since it can oxidize to form CO2 in the atmosphere; but it is just part of the larger problem surrounding our unsustainable use of resources, of which CO2 is the flashing neon sign--so to speak.

 

And again, that was mainly why I posted that information about land-use changes (with "changes" being the key word there). This also speaks to that atmosphere-to-soil connection. It is well known that poor land use can make many problems worse. It is not as widely known that changes in how we use land can mitigate and even correct many of our socio-economic problems, as well as most of our environmental problems.

 

But it shouldn't be too surprising, since history is full of stories about great civilizations that overused the land and then quickly found themselves constrained in an unsustainable position. Technology can extend the limits of those constraints, which are imposed by physics, but in the end we are still limited by those same basic constraints.

===

 

If these complexities aren't clear, or if I made mistakes, please ask a question or two; but....

 

So this is a view of why CO2, instead of methane or water vapor, is more focused upon by the people who have studied our biogeochemosphere enough to comprehend the relative risks across time and borders.

===

 

Do you see how we have been unintentionally changing (and increasingly so) that ultra-thin layer of atmosphere you mentioned?

 

Since that thin layer is so critical and influential, and now that our eyes have been opened to how thin and delicately balanced that layer is....

 

Shouldn't we be doing this intentionally, toward some purpose, with thought to the future?

 

~ :huh:

 

 

p.s. I'm assuming true value lies in the future, which is why we invest in it... right?

[Universal Student]

Again, I agree with much of what you said.

 

Having said that, I am stocking up on wood, coal, and other fuel to cope with the coming Ice Age. I’ll build a big greenhouse out back, with a heated roof to melt the snow in the summertime, so that what little sunshine there is can get through. I have three wood burning stoves and one small coal burning stove. I live in a area where there is a lot of firewood right across the street, but I am also stockpiling firewood and other fuel. Fuel will be come scarce and expensive rather quickly.

[CraigD]

Having said that, I am stocking up on wood, coal, and other fuel to cope with the coming Ice Age.

Unless you expect to live for many thousands of years, you’re ill-advised to make personal preparations for the next glacial period, because it’s not expected to occur for about 10,000 to 50,000 years.

 

It’s important to be mindful and careful, I think, with the term “ice age”. As a geological term, it refers to a period in which Earth has large ice sheets, such as those on Antarctica and Greenland. In this sense, there’s no ice age coming, as we’re still in the one that started about about 2,580,000 years ago.

 

Within an ice age like our present one, ice sheets expand and shrink to cover more and less of the surface. A period where the ice sheets cover more than on average is called a glacial period, one where it covers less, an interglacial period. We’ve been in an interglacial period for about the past 10,000 years, and as I mentioned above, are expected to remain in it for at least another 10,000.

 

Though the term “ice age” gets bandied about to mean many different things, which can be confusing, so on the principle that it’s good to have different words and phrases to name different things, I think it’s better to describe the coming glacial period as “the next glacial period” rather than “the coming ice age”.

 

As has been discussed in this and many other threads, were it not for the unusual high concentration of greenhouse gasses that has occurred since humans began transferring large amounts of carbon from reservoirs such as coal, oil, and limestone deposits into the air by burning and heating them, the Earth would be in period of gradual cooling leading to the next glacial period. Because of our carbon-releasing ways, however, we’re in a warming period, likely to last for at least 100 years.

 

(Sources: wikipedia articles Quaternary glaciation, glacial period, carbon cycle)

 

I’ll build a big greenhouse out back, with a heated roof to melt the snow in the summertime, so that what little sunshine there is can get through.

There’s no scientific theory or evidence for an impending sunshine shortage. Though the solar output varies in roughly 11 year cycles, it’s a small variance, about 0.1%. In the long term, stellar physics, which is pretty solid science, tells us the Sun will get steadily brighter, at a rate of about 1% every 100,000,000 years. Life on Earth as we presently know it will be impossible in about 1,000,000,000 years – a bit of a long time scale to worry about even for people who think they might live thousands of years. :)

 

(Sources: wikipedia articles solar variation, formation and evolution of the Solar System)

 

I have three wood burning stoves and one small coal burning stove. I live in a area where there is a lot of firewood right across the street, but I am also stockpiling firewood and other fuel. Fuel will be come scarce and expensive rather quickly.

I think you’re reasonable and correct to expect the scarcity and cost of fuel to increase in our lifetimes. The cost, though not the scarcity, has already increased a lot in the 51 years I’ve been alive. However, other than short term fluctuations due to market conditions, I don’t expect fuel, to become scarce and expensive quickly, especially coal, as best estimates put their proven reserves at more than 100 years current production.

 

(Source: wikipedia article coal)