Maggie's Farm

Jim: The great tragedy of Science — the slaying of a beautiful hypothesis by an ugly fact.

Global warming is based on a testable, causative model founded in basic physics, as understood for more than a century. See See Arrhenius, On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground, London, Philosophical Magazine and Journal of Science 1896.

Assistant Village Idiot: "Based on" in the sense of an idea that we think might be related to a second idea, which in turn depends on a third doesn't count.

Not sure what you are trying to say, but the greenhouse effect is due to basic physics. The Earth’s mean temperature without the greenhouse effect would be a chilly ≈-18°C rather than the balmy ≈+15°C that it is.

Assistant Village Idiot: If it counted, we would have seen more warming in the last 20 years.

GISTEMP, 1998 to present: +0.184°C/decade

Jim: It's all based on computer models, not supported by empirical data.

Arrhenius didn't have a computer. His calculations were based on fundamental physics. See See Arrhenius, On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground, London, Philosophical Magazine and Journal of Science 1896.

indyjonesouthere: Earth warming PRECEEDS co2 by about 800 years.

CO2 is both cause and effect in the climate system. As the Earth warms, the oceans can hold less CO2, which results in higher atmospheric CO2, which warms the Earth, a positive feedback. Conversely, as the Earth cools, the oceans can hold more CO2, which results in lower atmospheric CO2, which cools the Earth. Another positive feedback is due to ice formation which changes the Earth's albedo. This results in a seesaw climate pattern that cannot be explained by orbital variations alone.

See Pedro et al., Tightened constraints on the time-lag between Antarctic temperature and CO2 during the last deglaciation, Climate of the Past 2012: "Antarctic ice cores provide clear evidence of a close coupling between variations in Antarctic temperature and the atmospheric concentration of CO2 during the glacial/interglacial cycles of at least the past 800-thousand years... we show that the increase in CO2 likely lagged the increase in regional Antarctic temperature by less than 400 yr and that even a short lead of CO2 over temperature cannot be excluded."

indyjonesouthere: You refused to view a video I posted which was the best known explanation for changes in climate, both increases and decreases.

If you have it in text form, preferably a journal paper, we'll take a look. Meanwhile, you ignored our comment as to how CO2 can act as cause and effect, so that there may be delay involved between warming and CO2. We provided a citation to the primary literature.

Looks very similar to the graph in °K since the last glaciation. So?

drowningpuppies: Absolutely nothing in the past 100 years or so is abnormal in the rate of temperature change.

The graph you provided does nothing to support that contention.

drowningpuppies: Could y'all be more specific?

Sure. Three problems:

1) The most obvious is that it minimizes the differences over time. It could just a well be body temperature varying from 310°C to 314°C, the former being normal, the latter being dangerously high.

2) But leaving this aside, a graph of the last 100 years doesn't show whether or not it is an abnormal in the rate of temperature change, which requires looking at longer periods.

3) It's not the current temperature that are considered dangerous, but the projected temperatures due to continued global warming from human emissions.

Z: 310K to 314K

drowningpupppies: The graph is what it is.

Sure. It's showing the Earth's mean temperature in relation to absolute zero. Not sure what that is supposed to mean, but it is what it is.

drowningpupppies: please explain what is the 'normal' temperature of the Earth.

Actually, you introduced the term "abnormal", so it would seemingly be up to you to say what you mean.

What is of importance — to humans, at least — is climate stability. Humans built their civilizations during a period of relatively stable climate, on which they are now dependent.

drowningpupppies: Are you now suggesting that this short time period is significant to the rate of change of temperatures or should we look at a longer period?

We responded to the claim that more warming was expected in the last 20 years, when the rate of warming is within the estimated rate of warming.

drowningpupppies: So far temperatures have not matched the projections.

GISTEMP, 1998 to present: +0.184°C/decade

drowningpuppies: Are y'all having difficulty converting K to C?

That wasn't the question, but why you chose to show absolute zero on a chart concerning global mean temperature over the last century. It's almost as if you are trying to hide rather than reveal.

drowningpuppies: Now you're being obtuse.

Now you're being obtuse. You introduced the idea of "normal", which most people would read as what is consistent with natural rates of change, but then you pretend you didn't know what it meant.

drowningpuppies: Are you claiming the climate is becoming unstable?

That's correct. Earth's climate is going through a rapid and chaotic change due to anthropogenic emissions of greenhouse gases. How the excess heat will be distributed in the climate system is still obscure.

drowningpuppies: Was that the actual projection made before 1998?

Climate sensitivity has long been estimated at 2-5°C per doubling of CO2. The rate of change of 0.184°C per decade over the last 20 years is consistent with a climate sensitivity of about 3¼°C.

drowningpuppies: The temps are there in the graph provided by Gistemp.

Actually, GISTEMP is an estimate of temperature anomaly, so that's another problem with the graph. Here's the actual graph from GISTEMP.

drowningpuppies: Parsing definitions again.

If by "parsing" you mean citing the primary scientific literature, then sure.

drowningpuppies: No proof the climate is becoming "unstable".

The Earth's climate system is complex, and the heat will not be distributed evenly through the climate system. For instance, the higher latitudes will warm more than lower latitudes. This will cause changes in air and sea currents with chaotic results.

drowningpuppies: Your last comment doesn't answer the question asked.

It does The amount of warming is dependent on climate sensitivity. Climate sensitivity has long been estimated at 2-5°C per doubling of CO2, and that is consistent with observed warming.

drowningpuppies: That's an assumption and certainly not proof of an "unstable" climate

What? An assumption that the Earth's climate system is complex?


Climate is a canonical example of a complex system.

drowningpuppies: but if it were true please describe your assumed "chaotic" results?

A simple example would be the melting of ice caps disrupting ocean currents causing changes to regional climate.

drowningpuppies: Your assumption was after the comma.

Z: ", and the heat will not be distributed evenly through the climate system."

It's not an assumption. The Arctic is warming faster than the rest of the globe.

drowningpuppies: So what "chaos" would ensue, assuming the ice caps melt?

Freshwater melt could interfere with the Atlantic Meridional Overturning Circulation. If so, the effects would be very difficult to predict due to sensitivity to initial conditions.