Thank you GIGO … that Nature article is spot-on what I was looking for … I’ll be digesting the Feldman et al letter over the weekend …
I was answering Quartz’ comment about “correlation is not causation!” … of course ther’s a correlation between solar flux and global temperatures, we know the cause of this in very clear terms …
Also noteworthy is that the premise of the movie Soylent Green (1973) is climate change and global warming … these ideas have been around the better part of 50 years … the main difference is computers are fast enough today to run numerical models … and getting faster by the day …
You haven’t connected climate forcing to temperature in a quantitative way … because when you do you’ll find the logarithmic function the least of the Alarmists’ problems …
I am genuinely surprised … I had thought the 1.72 W/m[sup]2[/sup] number had been already confirmed … is this really that hard to measure? … anyway, that’s the clear sky value and of course perfect atmospherics will give the theoretical value, but rarely are the atmospherics perfect and so actual forcing is substantially lower …
The good news is that dealing with CO[sub]2[/sub] pollution will be easier than dealing with deforestation …
You’re right, I mentioned temperature but quantified CO2 concentrations relative to forcing rather than temperature. My original statement was “The warming caused by the radiative transfer effects of CO2 and other GHGs and their feedbacks are well quantified and observations match the CO2 concentrations that have accumulated since industrialization”, but what I showed was that the forcing due to CO2 etc. was well quantified. I did, however, say that “What is controversial is how forcings relate to changes in key climate parameters, particularly temperature, but even those arguments have well-bounded limits for climate sensitivity”. This is also quantifiable, but the exact quantitative relationship of CO2 forcing to temperature change under present conditions is much more complex and still the subject of some controversy. However, what is important for policy purposes is that there is a definite lower limit and the magnitude of the change and the speed with which it will happen are both significant.
The most often cited metric describing this relationship is equilibrium climate sensitivity – defined as how much temperature will increase at equilibrium when CO2 doubles. There’s broad agreement that it’s between 1.5°C to 4.5°C, a range that’s been cited more or less the same way for over 20 years. The IPCC no longer cites a “most likely” value within that range. Compounding the argument is that the probability density function of ECS estimates from many sources tends to be a skewed distribution with an early peak and a long tail at the high end. A reasonable estimate of most likely ECS is to take the median (not the mode) of the distribution, so that half the probabilities are above and half below the selected point. In most analyses the median yields a most likely value for ECS of around 3°C, meaning that, when CO2 doubles, and all feedbacks are taken into account, the temperature will stabilize around 3°C warmer than the reference temperature and CO2 concentration.
Well, of course Global Warming is also caused by a number of factors- the biggest warming gas is actually water vapor.
The thing is -* the recent rapid increase* is certainly most caused by humans with CO2, etc.
Tht doesnt mena humans are 100% responsible for all the C02 or all the water vapor or all the other greenhouse gases- they have been around since just about the start. It doesnt mean there are not other factors that coming in- long term slow cycles do certainly occur.
But there is no doubt that most of the recent rapid increase is human caused.
I realize you’re not trying to argue against AGW, but I have to point out that this example is a typical irrelevancy that one sometimes hears from climate deniers. The absolute amount of water vapor in the atmosphere globally, on average, is directly related to temperature. As temperatures rise, absolute humidity increases because the air’s capacity for water vapor increases. Generally speaking, tropospheric water vapor is not an independent climate forcing but a direct feedback that amplifies other forcings, particularly that of CO2, approximately doubling its impact.
A good illustration of how big the human influence has been is the historic CO2 level. If you drew a chart of CO2 levels over the past million years, it would vary between a consistent low of about 180 ppm at the depth of ice ages to a consistent high of about 290-300 ppm at the peak of interglacials. If you then wanted to add modern-era CO2 to the chart, it would be completely off the chart. You’d have to expand the scale, because it’s now over 400 ppm and probably can’t be stopped before it’s well over 600 and probably 800. And those changes are occurring, not over thousands of years, but within decades.
But if the temperature decreased in a global sense from 2018, with 2017 and 2016 being much hotter, the short-term coloration isn’t trending upward either.
Two or three years is far too short a timescale to detect any “trend” in global temperature, as annual temperature fluctuations outweigh small amounts of global temperature rise.
Anyway, what do you mean by “if the temperature decreased in a global sense from 2018”? There isn’t any global temperature change from 2018 yet, because it still is 2018. Early in 2018, for that matter.
This - 800ppm especially - seems more like pessimism that anything grounded in scientific objectivity. The IPCC Representative Concentration Pathways are still illustrative. Only the worst one of these takes us over 800ppm by end-of-century, and the second worst takes us over 600. The third worse to ~600. There is nothing that has changed since the RCPs were developed to lock us out of any of those pathways.
For what it’s worth, if I were a betting man (hey, I am, but this is too long-term of a bet to be meaningful…), I’d bet we’ll peak between 500 and 600 ppm.
That explains why I can’t find those numbers on the internet … temperature is easy to calculate with S-B if we know the emissivity values … how hard could it be to find? … just shine a light on a gas and measure the temperature … Surely, someone is working on this …
You’re misunderstanding what “climate” means in this context. The paper is talking about parts of the ionosphere at altitudes of the order of ~300 km, which for all practical purposes is outer space. What little atmosphere exists here is comprised of ionized plasma, which is naturally affected by magnetic field changes. The paper discusses changes in maximum electron density and ion temperature at these altitudes. Where do you see any linkage whatsoever to climate on earth?
What does that indicate to you? Do you think this represents the start of a downward trend? Obviously you think this has some importance, so spell it out for us.
And February will be cooler than July … tomorrow morning will be cooler than this afternoon … that’s all the subject of dynamic meteorology …
Global warming is based on the average temperature between 1968 and 2017 being higher than the average from 1918 to 1967 … and the temperature average will be even higher from 2018 to 2067 … that’s the subject of climatology …
See the difference? … in the first case we use dt as our time interval … in the second we use 50 years …
Where I live, today was cooler than yesterday and the day before, but I’m pretty sure that spring and summer are coming!
2016 was the hottest year on record in NOAA’s 138-year history. 2015 was the second hottest on record, and 2017 the third hottest. Temperature trends are not uniform or linear year-to-year, but the long-term trend is unequivocal, and so are the reasons for it. I have no idea what you’re trying to prove with that statement.
So the new 1998 is 2016, that figures, it is the same old flawed and discredited argument that skeptical scientists (the few that remain) warned their followers not to use:
“You’ve all seen articles say that global warming stopped in 1998. Well, with all due respect, that’s being a little bit unfair to the data…it was a huge El Niño year, and the sun was very active in 1998…make an argument that you can get killed on, and you will kill us [skeptics] all…if you lose credibility on this issue, you lose the issue.”
Patrick Michaels
6 September 2009
The hottest year we know of was 250,000,000 BC … although it’s fair to assume 4,700,000,000 BC was even hotter … but let’s not nitpick among friends eh? …
As an aside, Patrick Michaels is a funny guy, though not intentionally. He’s a typical climate change denier: a paid shill for the fossil fuel industry, and works as an advisor to the right-wing Cato Institute that was founded by Charles Koch to disseminate right-wing and libertarian propaganda. Michaels has managed to distinguish himself by being wrong about practically everything.
And before anyone else gets the wrong idea, there are good natural explanations of why was that… the same warming gases were present then, what climate scientists are warning about nowadays. For the environment it makes no difference that there were released by nature before (in a long period of time, but eventually at deadly levels), it is the same stuff and the environment reacts to the accumulation of global warming gases (that acidify the oceans too) just like in the past.
There’s a lot wrong in this one statement/question of yours.
(1) First of all, it misses the point: The point being made is that the radiative effect of CO2 (while way more complicated than you have imagined here) is pretty well-understood. What is not as well understood is the feedbacks in the climate system: For example, as the Earth warms, some land and sea ice melts in the polar regions and that decreases the reflectivity of the Earth, so this tends to cause more warming. This is called “a positive feedback” (“positive” because it amplifies the original effect). Similarly, as the Earth warms, more water vapor evaporates into the atmosphere and its concentration thus increases and, since water vapor is a greenhouse gas, that causes more warming, another positive feedback. Finally, there are clouds, i.e., water vapor condensed into droplets…which are complicated because clouds can cause both cooling (by reflecting solar radiation) and warming (by increasing the greenhouse effect). And, furthermore, how cloudiness will change as the Earth warms is not easy to predict. So, it turns out that the cloud feedback is the biggest source of uncertainty in determining the climate sensitivity, i.e., how much the Earth will warm in response to, say, a doubling of CO2 levels. [And, there are feedbacks to other parts of the process too since, for example, a warming Earth can cause changes in the uptake of CO2 by plants and oceans or can cause the release of methane from melting permafrost and so forth.]
(2) Second of all, the radiative effects of CO2 are more complicated than Stefan-Boltzmann. That applies to radiating surfaces of opaque objects. Here, we are talking about a gas that radiation passing through can be absorbed and radiation can also be emitted. Also, for gases like CO2, the emissivity / absorptivity tend to occur in sharp lines and bands, which are quite complex. Nonetheless, as I (and I believe wolfpup) noted, the radiative transfer codes that compute the radiative forcing due to increases in CO2 are quite well-advanced and the uncertainties in this radiative forcing is considerably better determined than the next step of figuring out how that radiative forcing translates into a change in temperature (where the feedbacks come in).