It was a head exploding winter for climate deniers. While Boston and the Northeast set records for snow fall, Western North America remained warm and ominously dry, forcing a re-routing of the famous Iditarod 1000 mile Dogsled race in Alaska.
The other night, science phobic Senator Ted Cruz was challenged about climate change in an interview with Seth Meyers of the Late Night Show, and responded weakly that there was snow and ice in New Hampshire. It’s pathetic to imagine that a United States Senator has a view so pinched that he is unable to imagine a larger world outside of the US East Coast, a larger world where the planet experienced a record warm winter.
The Earth just had its warmest winter on record, the National Oceanic and Atmospheric Administration announced Wednesday.
Winter is defined as the months of December, January and February in the Northern Hemisphere, and 90% of the world’s population lives in the Northern Hemisphere. Those months are summer in the Southern Hemisphere.
Specifically, the Northern Hemisphere had its warmest winter on record, and the Southern Hemisphere had its fourth-warmest summer.
It’s also the warmest year-to-date on record, NOAA said. February itself was the second-warmest February on record.
Temperatures for December–February beat the previous winter record in 2007 by 0.05 degrees, NOAA’s National Climatic Data Center reported. Global temperature records go back to 1880.
Global temperatures for December-January. Areas in red and pink were warmer-than-average, while areas in blue were cooler-than-average. Eastern North America was one of the few land areas that saw an unusually cool winter. (Image: NOAA/NCDC)
One of the planet’s only land areas that had a cooler-than-average winter was eastern North America, which includes the eastern United States and eastern Canada.
It was a tale of two winters across Canada, as snowstorms pounded the Atlantic provinces and unusually warm temperatures spurred an early thaw on the West Coast, says David Phillips, Environment Canada senior climatologist.
The divergence between the two coasts was profound, as British Columbians jogged shirtless while East Coasters shivered through storm after storm, Phillips said. And in the far North, Iqaluit saw records felled by the deep freeze.
“Seldom have we seen a winter of marked weather contrasts from coast to coast,” Phillips said.
TAHOE CITY — There’s something disconcerting about life at Lake Tahoe these days.
It’s still winter, but visitors are renting bikes instead of snowshoes and kayaks instead of skis. Come summer — without last-ditch torrential rains — the lake level is expected to be at such a historic low that some marinas will have to dredge for boats to launch. Jumping off the end of a pier could result in a rock-hard landing.
California’s epic drought, entering its perilous fourth year, has combined with a pattern of warming temperatures to cast a “Twilight Zone” quality on one of the state’s most popular winter destinations and iconic landmarks.
Alaska is synonymous with bitter cold, ice and snow. But that may not last. This year, for only the second time in its history, the iconic Iditarod Trail Sled Dog Race has been forced to change course due to a lack of snowfall. Though unfortunate, it’s not exactly unexpected, as 2014 was the warmest year on record in Alaska and the first year ever recorded where the temperature never dropped below zero in Anchorage. So far this winter, Anchorage (where the race traditionally starts) has gotten less than 20 inches of snow — meaning that Boston’s big storm dropped more snow in a couple of days than Anchorage has gotten all season!
Scenes like this have become more common in Alaska. The 2014 Iditarod here was a near disaster for Mushers, and the 2015 route was changed in part as a response to racers, whose teams and gear took a terrible beating last year due to snowless conditions like this.
As we continue to emit greenhouse gasses, Alaska’s climate will continue to change. It’s already started, according to the National Climate Assessment. So far, emissions have driven temperatures up by 3 degrees Fahrenheit over the past 60 years, and winter temperatures an astonishing 6 degrees. This means it’s warming at twice the pace of the rest of the U.S. All this warming has obvious implications for those that depend on the snow, as warm waters off the coast mean precipitation falls as rain instead of snow. Iditarod organizers said that in some parts of the trail, the lack of snow exposed willow roots, rocks and boulders that they’d never seen before.
While this may seem like a minor issue of concern primarily to sled dog enthusiasts, it serves as a warning to us all. And I don’t just mean all of us native Alaskans who come from a family of mushers, or even all of us who love snow sports. I mean every single person who cares about preserving pristine wild spaces and enjoying any kind of outdoor sport. From changing the Iditarod in Alaska to dismantling ski lifts in Europe and canceled World Cup races, from a tennis player in The Australian Open getting so overheated he saw Snoopy, to football players getting heatstroke in the U.S., it doesn’t take much looking to see that a warmed world is bad news for athletes of all kinds.
See Meyers interview with Senator Cruz, 4 minutes, below:
Clearly we need to run some workshops on climate denial talking points for Late Night TV hosts, but challenges like these are going to get more intense and more frequent for media hopping politicians.
We should follow the science by cherry picking the parts that confirm my bias.
Global Warming was changed to Climate Change because the Earth is not warming (CONSPIRACY!!!!)
Rubbish.
I’m sure many readers have heard the phrase that “most scientists studying climate agree with the theory that proposes that humans affect climate change.”
The questions is what is exactly that those scientists agree on? And who are these scientists? What they agree on is the fact that human activities, to some degree, affect climate change and among those many scientists who agree with the previous statements are many of those so-called ‘skeptics’.
The more I witness seminars and read papers, the conclusion that appears before me more frequently is that THERE IS NO WAY TO MEASURE WITH TOTAL ACCURACY HOW MUCH HUMAN ACTIVITY AFFECTS PLANETARY CLIMATE.
This is because the models used by the IPCC simply do not have the ability to measure the interactions between all elements involved in climate change.
Scientists can’t even imagine how the interactions occur between these elements, much less model them. Therefore, it is irresponsible to establish that human activity is the main reason for current or future variability in the climate of the Earth.
That theory is simply not scientific.
The other statement that is commonly accepted is that the incidence of meteorological phenomena is a sign of drastic changes in climate and even worse, that the incidence and these drastic changes are caused by human acitivity.
Again, there is no scientific basis to verify either of these two theories and any alleged science person who tells you that the three statements presented here are definitely true is at the very least ill informed.
unfortunately, you cant just say, “Some unknown process is changing the planet’s climate in exactly the same way scientists predicted greenhouse gases would 40 years ago.”
You have to come up with an alternative explanation. The IPCC has explored all the alternative explanations, ie solar, ie random, ie ocean currents – and none of them can fit the bill – yet greenhouse gases fit the observed complex changes exactly. See here from a former denier: https://www.youtube.com/watch?v=Sme8WQ4Wb5w
and see the history from a long time expert
Here’s Luis demanding TOTAL ACCURACY?. Hey, Luis—here’s a “total accuracy” plan for you. The next time you see a low-slung house-cat sized critter with longitudinal black and white stripes waddling across your yard, go out and pick it up by the tail so that you can examine it closely enough to determine what it really is. If it looks like a skunk, walks like a skunk, and smells like a skunk, it’s probably not your neighbor’s pussycat—and you would be stupid to demand the “total accuracy” of getting sprayed before you accept that.
GHG and AGW are things that man has known about and discussed for many decades, centuries even, but climate science is really only 50 or 60 years old because it took the advent of computers and satellites for it to “take off”. We are gathering better data and processing it better all the time, but computer models are still not up to the task of approaching “total accuracy”. I recently read that the hurricane forecasting models take six days of computing time to come up with a NEAR “totally accurate” 3-day forecast, and that’s why they speak of probabilities rather than certainties as they try to give useful and timely info to the public. Good enough is good enough—-the precautionary principle rules there, just as it should with climate change.
It’s the same with AGW. Peter has commented here about what’ we’ve seen with our “climate change skunk examining”, and you should review those clips. You need to reexamine the thinking that led you to make such misleading, definitive, and unsupportable declaratory statements (aka bald assertions) as:
“This is because the models used by the IPCC simply do not have the ability to measure the interactions between ALL elements involved in climate change”. The key word is “ALL”, of course—-60 years ago there was no IPCC and no substantial computer modeling capability. We’ve come a long way.
“Scientists can’t even imagine how the interactions occur between these elements, much less model them.” Where have you been? Scientists have indeed “imagined” and “modeled” the “interactions between elements”, albeit not with “total accuracy”. Even the deniers have used their “imaginations” to make use of what we’ve learned to sow FUD
“The other statement that is commonly accepted is that the incidence of meteorological phenomena is a sign of drastic changes in climate and even worse, that the incidence and these drastic changes are caused by human activity”. Again, models have been used to both recreate the past and predict the future, and have done so with much accuracy (even if not “total”). See Peter’s comment and think of skunks.
As to “Again, there is no scientific basis to verify either of these two theories and any alleged science person who tells you that the three statements presented here are definitely true is at the very least ill informed”. May I suggest that YOU are perhaps the one who is “ill informed”? Unless of course, your pedantry over “total” and “definitely” is motivated not by a concern for the integrity of the science but by politics or religion?
Surprise! For the first time since the climate debate began, a team of researchers led by the U.S. DOE Lawrence Berkeley National Laboratory directly measured the contribution of increasing atmospheric carbon dioxide (CO2) to heating of the Earth (Nature).
Therefore, it is irresponsible to establish that human activity is the main reason for current or future variability in the climate of the Earth.
One word for you: stoichemistry.
1) We know the chemical reaction when hydrocarbons are burned -> it produces a known number of CO2 molecules for a known number of carbon atoms
2) We know how many atoms of carbon have been burned since 1850. It is measured in barrels of oil, tons of coal, and cubic meters of natural gas which has been sold and burned
3) The amount of CO2 produced by burning fossil fuels exactly matches the atmospheric concentration after things like carbon fixation are properly taken into account.
So, unless you are a crackpot who denies the physics of the greenhouse effect, it is perfectly obvious that humans are responsible for the warming the planet. 100% of climate scientists the world round agree that the planet is warming. And 97% of them agree that AGW is due to humans burning fossil fuels.
You have really missed the boat. And it is a well-lit, perfectly measured and freaking gigantic boat that you evidently can not see despite it being right in front of your face..
Not sure how “much” we know “exactly” and “perfectly” because it has been “properly measured and taken into account”, but you’ve done a good job of explaining in just a few words to Luis what the climate modelers have done, and why we are so sure of AGW—-he has indeed missed the “gigantic boat”.
PS One word for you: stoichiometry (unless you’re making a joke about philosopher-chemists)
And here we see demonstrated he old trick of one of the conspirators reinforcing the untruth that he conspires to “make true”. It’s not “rubbish” but a deliberate plan.
My preferred term is AGW, because that’s what we have—-man-caused and unprecedented global warming due to our burning of fossil fuels. The first step of the conspirators was to take “man-caused” out of there, and then it was just “global warming”, following that with “No, it’s really climate change because sometimes it gets warmer and other times colder. Look at Boston and the snowballs thrown on the Senate floor by Frosty the Senator for proof of how cold it’s been.”
Then you sow FUD by cherry-picking and distorting “data” to try to obfuscate truth a bit longer. Oh, yeah, confuse them with “data” from satellites but don’t mention the 1001 other bits of clear evidence that the Earth is “on fire”. Be glib and personable and folksy—don’t wear a tie. Cruz is a lot smarter than Rick Perry, so he doesn’t have to wear “Look smart” glasses, but he is a far bigger slimeball and lying POS.
The sad thing is that some wimpy scientists have done their share by going along with the move from AGW to global warming to climate change. I much prefer the bluntness and simple truth of “we’re the cause of it all and if we don[‘t recognize that and do something soon, we’re f**ked”.
So to sum up, although the terms are used interchangeably because they are causally related, ‘global warming’ and ‘climate change’ refer to different physical phenomena. The term ‘climate change’ has been used frequently in the scientific literature for many decades, and the usage of both terms has increased over the past 40 years. Moreover, since the planet continues to warm, there is no reason to change the terminology. Perhaps the only individual to advocate the change was Frank Luntz, a Republican political strategist and global warming skeptic, who used focus group results to determine that the term ‘climate change’ is less frightening to the general public than ‘global warming’. There is simply no factual basis whatsoever to the myth “they changed the name from global warming to climate change”.”
The “Climate change” canard works with the “Fox & Friends” crowd who, we can charitably say, have not been paying much attention.
The primary answer is to point out to deniers that the UN body formed to deal with this issue in 1989, 26 years ago now, – was named the Intergovermental Panel on – say it with me – Climate Change.
What’s extraordinary about the paper below is not the title and date it was written, but that this guy calculated a climate sensitivity that’s right in range of the sensitivity from the paleorecord and the modern supercomputers.
—————————-
The Carbon Dioxide Theory of Climatic Change
GILBERT N. PLASS
(Manuscript received August 9, 1955)
The most recent calculations of the infra-red flux in the region of the 15 micron CO2 band show that the average surface temperature of the earth increases 3.6° C if the CO2 concentration in the atmosphere is doubled and decreases 3.8° C if the CO2 amount is halved, provided that no other factors change which influence the radiation balance. Variations in CO2 amount of this magnitude must have occurred during geological history; the resulting temperature changes were sufficiently large to influence the climate. The CO2 balance is discussed. The CO2 equilibrium between atmosphere and oceans is calculated with and without CaCO3 equilibrium, assuming that the average temperature changes with the CO2 concentration by the amount predicted by the CO2 theory. When the total CO2 is reduced below a critical value, it is found that the climate continuously oscillates between a glacial and an inter-glacial stage with a period of tens of thousands of years; there is no possible stable state for the climate. Simple explanations are provided by the CO2 theory for the increased precipitation at the onset of a glacial period, the time lag of millions of years between periods of mountain building and the ensuing glaciation, and the severe glaciation at the end of the Carboniferous. The extra CO2 released into the atmosphere by industrial processes and other human activities may have caused the temperature rise during the present century. In contrast with other theories of climate, the CO2 theory predicts that this warming trend will continue, at least for several centuries.
By no later than 1872 John Tyndall was not only using “climate (climatic) change” in regard to slight changes in GHG concentrations, he explicitly included CO2 as a named constituent second only to water vapor.
John Tyndall, Contributions to Molecular Physics in the Domain of Radiant Heat, 1872, p.37
“…Now if, as the above experiments indicate, the chief influence be exercised by the aqueous vapour, every variation of this constituent must produce a *change of climate.* Similar remarks would apply to the *carbonic acid* diffused through the air, while an almost inappreciable admixture of any of the stronger hydrocarbon vapours would powerfully hold back the terrestrial rays and produce corresponding *climatic changes.* It is not, therefore, necessary to assume alterations in the density and height or the atmosphere to account for different amounts of heat being preserved to the earth at different times; a slight change in the variable constituents of the atmosphere would suffice. Such changes in fact may have produced all the mutations of climate which the researches of geologists reveal. However this may be, the facts above cited remain firm; they constitute true causes, the extent alone of the operation remaining doubtful.”
My senator has clearly given the subject much thought. I’d never heard these talking points before.
“There’s been zero warming for the past 17 years, none whatsoever.”
“Remember, it used to be called global warming and then magically the theory turned to climate change.”
Same old same old from Ted Cruz.
We should follow the science by cherry picking the parts that confirm my bias.
Global Warming was changed to Climate Change because the Earth is not warming (CONSPIRACY!!!!)
Rubbish.
I’m sure many readers have heard the phrase that “most scientists studying climate agree with the theory that proposes that humans affect climate change.”
The questions is what is exactly that those scientists agree on? And who are these scientists? What they agree on is the fact that human activities, to some degree, affect climate change and among those many scientists who agree with the previous statements are many of those so-called ‘skeptics’.
The more I witness seminars and read papers, the conclusion that appears before me more frequently is that THERE IS NO WAY TO MEASURE WITH TOTAL ACCURACY HOW MUCH HUMAN ACTIVITY AFFECTS PLANETARY CLIMATE.
This is because the models used by the IPCC simply do not have the ability to measure the interactions between all elements involved in climate change.
Scientists can’t even imagine how the interactions occur between these elements, much less model them. Therefore, it is irresponsible to establish that human activity is the main reason for current or future variability in the climate of the Earth.
That theory is simply not scientific.
The other statement that is commonly accepted is that the incidence of meteorological phenomena is a sign of drastic changes in climate and even worse, that the incidence and these drastic changes are caused by human acitivity.
Again, there is no scientific basis to verify either of these two theories and any alleged science person who tells you that the three statements presented here are definitely true is at the very least ill informed.
unfortunately, you cant just say, “Some unknown process is changing the planet’s climate in exactly the same way scientists predicted greenhouse gases would 40 years ago.”
You have to come up with an alternative explanation. The IPCC has explored all the alternative explanations, ie solar, ie random, ie ocean currents – and none of them can fit the bill – yet greenhouse gases fit the observed complex changes exactly. See here from a former denier:
https://www.youtube.com/watch?v=Sme8WQ4Wb5w
and see the history from a long time expert
Here’s Luis demanding TOTAL ACCURACY?. Hey, Luis—here’s a “total accuracy” plan for you. The next time you see a low-slung house-cat sized critter with longitudinal black and white stripes waddling across your yard, go out and pick it up by the tail so that you can examine it closely enough to determine what it really is. If it looks like a skunk, walks like a skunk, and smells like a skunk, it’s probably not your neighbor’s pussycat—and you would be stupid to demand the “total accuracy” of getting sprayed before you accept that.
GHG and AGW are things that man has known about and discussed for many decades, centuries even, but climate science is really only 50 or 60 years old because it took the advent of computers and satellites for it to “take off”. We are gathering better data and processing it better all the time, but computer models are still not up to the task of approaching “total accuracy”. I recently read that the hurricane forecasting models take six days of computing time to come up with a NEAR “totally accurate” 3-day forecast, and that’s why they speak of probabilities rather than certainties as they try to give useful and timely info to the public. Good enough is good enough—-the precautionary principle rules there, just as it should with climate change.
It’s the same with AGW. Peter has commented here about what’ we’ve seen with our “climate change skunk examining”, and you should review those clips. You need to reexamine the thinking that led you to make such misleading, definitive, and unsupportable declaratory statements (aka bald assertions) as:
“This is because the models used by the IPCC simply do not have the ability to measure the interactions between ALL elements involved in climate change”. The key word is “ALL”, of course—-60 years ago there was no IPCC and no substantial computer modeling capability. We’ve come a long way.
“Scientists can’t even imagine how the interactions occur between these elements, much less model them.” Where have you been? Scientists have indeed “imagined” and “modeled” the “interactions between elements”, albeit not with “total accuracy”. Even the deniers have used their “imaginations” to make use of what we’ve learned to sow FUD
“The other statement that is commonly accepted is that the incidence of meteorological phenomena is a sign of drastic changes in climate and even worse, that the incidence and these drastic changes are caused by human activity”. Again, models have been used to both recreate the past and predict the future, and have done so with much accuracy (even if not “total”). See Peter’s comment and think of skunks.
As to “Again, there is no scientific basis to verify either of these two theories and any alleged science person who tells you that the three statements presented here are definitely true is at the very least ill informed”. May I suggest that YOU are perhaps the one who is “ill informed”? Unless of course, your pedantry over “total” and “definitely” is motivated not by a concern for the integrity of the science but by politics or religion?
Surprise! For the first time since the climate debate began, a team of researchers led by the U.S. DOE Lawrence Berkeley National Laboratory directly measured the contribution of increasing atmospheric carbon dioxide (CO2) to heating of the Earth (Nature).
http://www.forbes.com/sites/jamesconca/2015/02/27/surprise-co2-directly-linked-to-global-warming/
One word for you: stoichemistry.
1) We know the chemical reaction when hydrocarbons are burned -> it produces a known number of CO2 molecules for a known number of carbon atoms
2) We know how many atoms of carbon have been burned since 1850. It is measured in barrels of oil, tons of coal, and cubic meters of natural gas which has been sold and burned
3) The amount of CO2 produced by burning fossil fuels exactly matches the atmospheric concentration after things like carbon fixation are properly taken into account.
So, unless you are a crackpot who denies the physics of the greenhouse effect, it is perfectly obvious that humans are responsible for the warming the planet. 100% of climate scientists the world round agree that the planet is warming. And 97% of them agree that AGW is due to humans burning fossil fuels.
You have really missed the boat. And it is a well-lit, perfectly measured and freaking gigantic boat that you evidently can not see despite it being right in front of your face..
Not sure how “much” we know “exactly” and “perfectly” because it has been “properly measured and taken into account”, but you’ve done a good job of explaining in just a few words to Luis what the climate modelers have done, and why we are so sure of AGW—-he has indeed missed the “gigantic boat”.
PS One word for you: stoichiometry (unless you’re making a joke about philosopher-chemists)
yeah, I always forget that last “io”!
And here we see demonstrated he old trick of one of the conspirators reinforcing the untruth that he conspires to “make true”. It’s not “rubbish” but a deliberate plan.
My preferred term is AGW, because that’s what we have—-man-caused and unprecedented global warming due to our burning of fossil fuels. The first step of the conspirators was to take “man-caused” out of there, and then it was just “global warming”, following that with “No, it’s really climate change because sometimes it gets warmer and other times colder. Look at Boston and the snowballs thrown on the Senate floor by Frosty the Senator for proof of how cold it’s been.”
Then you sow FUD by cherry-picking and distorting “data” to try to obfuscate truth a bit longer. Oh, yeah, confuse them with “data” from satellites but don’t mention the 1001 other bits of clear evidence that the Earth is “on fire”. Be glib and personable and folksy—don’t wear a tie. Cruz is a lot smarter than Rick Perry, so he doesn’t have to wear “Look smart” glasses, but he is a far bigger slimeball and lying POS.
The sad thing is that some wimpy scientists have done their share by going along with the move from AGW to global warming to climate change. I much prefer the bluntness and simple truth of “we’re the cause of it all and if we don[‘t recognize that and do something soon, we’re f**ked”.
Regarding the use of Climate Change vs Global Warming, Cruz is 100% wrong in his assertion that this was some sort of ploy:
Once again, Skeptical Science has the facts on this, and why both terms are both legitimate, and while causally related, are two different things:
http://www.skepticalscience.com/climate-change-global-warming.htm
“Summary
So to sum up, although the terms are used interchangeably because they are causally related, ‘global warming’ and ‘climate change’ refer to different physical phenomena. The term ‘climate change’ has been used frequently in the scientific literature for many decades, and the usage of both terms has increased over the past 40 years. Moreover, since the planet continues to warm, there is no reason to change the terminology. Perhaps the only individual to advocate the change was Frank Luntz, a Republican political strategist and global warming skeptic, who used focus group results to determine that the term ‘climate change’ is less frightening to the general public than ‘global warming’. There is simply no factual basis whatsoever to the myth “they changed the name from global warming to climate change”.”
The “Climate change” canard works with the “Fox & Friends” crowd who, we can charitably say, have not been paying much attention.
The primary answer is to point out to deniers that the UN body formed to deal with this issue in 1989, 26 years ago now, – was named the Intergovermental Panel on – say it with me – Climate Change.
What’s extraordinary about the paper below is not the title and date it was written, but that this guy calculated a climate sensitivity that’s right in range of the sensitivity from the paleorecord and the modern supercomputers.
—————————-
The Carbon Dioxide Theory of Climatic Change
GILBERT N. PLASS
(Manuscript received August 9, 1955)
The most recent calculations of the infra-red flux in the region of the 15 micron CO2 band show that the average surface temperature of the earth increases 3.6° C if the CO2 concentration in the atmosphere is doubled and decreases 3.8° C if the CO2 amount is halved, provided that no other factors change which influence the radiation balance. Variations in CO2 amount of this magnitude must have occurred during geological history; the resulting temperature changes were sufficiently large to influence the climate. The CO2 balance is discussed. The CO2 equilibrium between atmosphere and oceans is calculated with and without CaCO3 equilibrium, assuming that the average temperature changes with the CO2 concentration by the amount predicted by the CO2 theory. When the total CO2 is reduced below a critical value, it is found that the climate continuously oscillates between a glacial and an inter-glacial stage with a period of tens of thousands of years; there is no possible stable state for the climate. Simple explanations are provided by the CO2 theory for the increased precipitation at the onset of a glacial period, the time lag of millions of years between periods of mountain building and the ensuing glaciation, and the severe glaciation at the end of the Carboniferous. The extra CO2 released into the atmosphere by industrial processes and other human activities may have caused the temperature rise during the present century. In contrast with other theories of climate, the CO2 theory predicts that this warming trend will continue, at least for several centuries.
http://onlinelibrary.wiley.com/doi/10.1111/j.2153-3490.1956.tb01206.x/abstract
http://onlinelibrary.wiley.com/doi/10.1111/j.2153-3490.1956.tb01206.x/pdf
By no later than 1872 John Tyndall was not only using “climate (climatic) change” in regard to slight changes in GHG concentrations, he explicitly included CO2 as a named constituent second only to water vapor.
John Tyndall, Contributions to Molecular Physics in the Domain of Radiant Heat, 1872, p.37
“…Now if, as the above experiments indicate, the chief influence be exercised by the aqueous vapour, every variation of this constituent must produce a *change of climate.* Similar remarks would apply to the *carbonic acid* diffused through the air, while an almost inappreciable admixture of any of the stronger hydrocarbon vapours would powerfully hold back the terrestrial rays and produce corresponding *climatic changes.* It is not, therefore, necessary to assume alterations in the density and height or the atmosphere to account for different amounts of heat being preserved to the earth at different times; a slight change in the variable constituents of the atmosphere would suffice. Such changes in fact may have produced all the mutations of climate which the researches of geologists reveal. However this may be, the facts above cited remain firm; they constitute true causes, the extent alone of the operation remaining doubtful.”