How helpful is the "skeptic" claim that "It's been warming since the end of the Little Ice Age" ...?

Question

... how helpful is that claim in informing us about man made global warming? The implication being of course, that some or perhaps all of the warming since then, must be natural!

How helpful is that line of reasoning? Clearly it's not wrong, but isn't the most likely explanation the increasing levels of greenhouse gasses in the atmosphere?I

Please don't get me wrong; I'm not claiming it is all down to GHG's, but is there any reason to believe that, in the absence of human influence, the world would still be warming naturally today?

If there is such reason, what is it?

Or, if we don't know, isn't cooling equally likely?

What does the data say (instrumental and proxy) and what is the best explanation?

Can you do better than simply stating some variant of "warming after the Little Ice Age"? ... which, I would suggest, is of no help at all!

Answer 1

Well, I think there are a few key points I'd make ...



1. Many people argue that global warming is possibly due to 'natural factors' or is part of some 'natural cycle'. Then they leave it at that, as if that is an explanation. It isn't. Natural factors or processes, by definition, can be identified, measured, quantified, and analysed. The planet can't just warm or cool. There has to a physical reason for that.



2. The Little Ice Age was caused, we think, by a drop in solar output but there are still questions about how it happened. For example, there are still arguments over whether it was localized in the Northern hemisphere or whether the entire planet experienced cooling. The role of ocean currents is still being discussed. However, the general theory is that a combination of the solar output and ash and dust from some large volcanic eruptions played a role. The reason the planet started to warm after the LIA was because solar output increased and volcanic activity settled back.



3. We know that this warming continued into the 20th century. But we also know it stopped being the dominant mechanism. How? What we saw was the planet starting to cool slightly. There was no significant change in solar output and some large volcanic eruptions along with an increase in the 1940s onwards of sulphur dioxide and aerosol production from industry. As we cleaned up our emissions by the 1970s, we started to see increasingly rapid warming. This warming, over the past 50 years, did not follow solar output - when output dropped, temperatures still rose.



4. This rise in temperature since the 1970s has entirely different characteristics to what we would expect if the dominant mechanisms were the same as those bringing us out of the LIA. It occurs mostly at night, which is hard to explain on the basis of changes in solar output or volcanos. We see warming of the troposphere and cooling of the stratosphere. Both are consistent with greenhouse gas increases. So although it is easy to argue that the same processes are at work now as brought us out of the LIA, that is no longer consistent with what we observe. It is not the primary reason our planet has warmed since 1970 and was a diminishing factor in the 20th century leading to that point.



5. Finally, I'm always concerned when people try to explain observations using every possible mechanism *except* the one they disagree with. It smacks of bias ... we've had all manner of 'explanations' including solar variation, orbital variations, changes in galactic cosmic rays, changes in albedo due to human activities, changes in the siting of weather stations, urban heat island effects, the adjustment methods used by scientists to combine datasets, and so on. We've had people argue that the warming is a continuation of the same factors that brought us out of the LIA, yet then argue the temperature paused. So is it, or isn't it warming the planet? And I could go on ... but the point is made.

Answer 2

It isn't very helpful to a socialist agenda. Facts and science are the worst enemy of Alarmists. It has been warming for 300 years. Obviously for most of that time, it wasn't from human emissions of CO2. The last hundred years is similar to the hundred years before that yet alarmists like Dirac/James/Pegminer want to blame any warming on humans. That is because their primary purpose is to exaggerate for their cause and their cause has nothing to do with science. If you believed in science and fact, it would be helpful to point out scientific observations. If your primary purpose was to exaggerate any recent warming to push a political cause, you would what alarmists do and try to minimize any of the previous changes.

Answer 3

It's only intended to distract. You'll notice that they never give the rate of warming over that time, because it's completely insignificant compared to the current warming.



They don't use real science, the try to sound "sciency".

Answer 4

The sun has become progressively more active since the 1700s. Could that not play a factor with the climate?



OK, the solar irradiance may not have increased sufficiently to explain all of it directly but maybe there are other factors? (The NOAA "adjustments" explain some of the temperature increase!)



Do the current computer climate models explain the past temperature changes as well as this paper? Whether the sun makes the changes itself or whether it is controlled by something else is a matter for debate.



http://www.thegwpf.org/professor-valentina-zharkova-the-solar-magnetic-field-and-the-terrestrial-climate/

Answer 5

Darwin, the Sun is your answer...here is something to ponder!



Solar rotation

Solar rotation varies with latitude because the Sun is composed of a gaseous plasma. The reason why different latitudes rotate at different periods is unknown. The rate of surface rotation is observed to be fastest at the equator, and to decrease as latitude increases. The solar rotation period is 24.47 days at the equator and almost 38 days at the poles.



Solar rotation is affected the gravitational pull from the gas giants, Jupiter, Saturn, Uranus and Neptune when there are in specific cyclic orientations in their specific orbits. The U/N 178 year cycle is imminent and is affecting the Solar rotation by speeding it up by days. When the sun's rotation speeds up, sun spots levels go down, TSI goes down and this causes global cooling. This is on going astrophysics research that is known to and ignored by the IPCC.



Zharkova et al's (2015) research is also ignored even though all her predictions are coming true.

Answer 6

The ice age is still here

Answer 7

First of all, someone who is a skeptic would want evidence that it actually was warming since the end of the Little Ice Age. For one thing, to say that it has been warming since the end of the Little Ice Age is kind of like saying that it has been getting windier since the wind started picking up or that it has been getting wetter since it started warming.



The real question is why has it been warming?

Answer 8

Well it is rather difficult to separate the two.

Undoubtedly it has been warming since the little ice age we can see the results in tide gauge data.

https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?id=120-022

I believe climate sensitivity is minimal, perhaps 0.5C for a doubling of CO2

The IPCC says 3.7 watts which is about 1C then fill it out with B.S. feedbacks.stating water is a powerful GHG (which it is) but completely ignoring that water vapor has powerful cooling effects as well.

It is my belief that our world wont hit the so called dreaded 2C warming and will struggle to reach 1.5 C warming.

Answer 9

'Warming' or cooling in the 'natural sense' of the word happens over geological time....that's usually millions of years with an occasional...every 100,000 plus years a sudden rise or sudden fall, but more generally a slowly rising or falling graph line. Our current situation has come about in 'historical time'....less than 200 years. Oddly this tracks the beginning of the Industrial Age and the ever increasing load of man made carbon and methane. Warming and cooling doesn't happen over such a short period of time in some natural sequence. This time it's different and ALL of the data, the science and the laws of atmospheric physics attest to that no matter what uninformed political views someone holds!

Answer 10

Sure.



Ever since the actual "big" Ice Age, the world has gone through periods of heat and periods of cold. There was a warming trend exactly like the one we're having now during Roman times and again during the Middle Ages, but the levels of CO2 remained the same.



Historically, the temperature changed, and we must attribute the change to natural climate drivers such as water vapor, solar activity, and all of the other greenhouse gases like methane with water vapor being the "major player" according to NASA . Of course CO2 is a greenhouse gas, but it has had very little impact since it makes up only 2% of the greenhouse effect.



What we must assume is that man made CO2 levels are not the primary cause of climate change, and what is not "helpful" is determining the exact way that CO2 makes it's 2% contribution and comparing levels of the CO2 to the rising temperature.



The best idea would be to study natural climate drivers like water vapor and see exactly how they have changed the temperature now and in the past.



And yes, as Don put it, we need to figure out what to do about the changing climate rather than pretending we can change it back next week.