Maggie's Farm

The actual projection with caveats: "future average precipitation is difficult to predict, but may likely not change substantially when measured by annual precipitation. However, there is high confidence in projections that even if precipitation remains stable or increases, drought severity and the number of dry years will increase, *even as more extreme precipitation events may occur*."


While climate change can be chaotic and hard to predict (like the weather), the rise in global mean surface temperatures is not nearly so intractable. However, we know from historical examples that even a couple of degree change can result in vast changes to regional climates. Knowledge of how this extra heat will affect various regions of the globe is still tentative.


The Gulf Stream brings tropical waters to the shores of western Europe, so the region is much warmer than it would be otherwise. (See Franklin, Chart of the Gulf Stream, Mount and Page 1769.) While the possible collapse of the Atlantic Meridional Overturning Circulation is far from certain, if it were to slow significantly, then western Europe could cool substantially.


There are multiple researchers using multiple methodologies reaching the same conclusion: the Earth's surface is warming due to human activities.

jack walter: The Earth heat up, the Earth cool down. It's been happening long before there were people.

What will those crazy scientists come up with next?! By the way, those same scientists, using much the same means, have determined that humans are unnaturally warming the Earth's surface. But whadda they know!? (None of this addresses the problems in Jack Hellner's article.)

Jim Alaska: On the other hand there are multiple researchers using multiple methodologies noting the earth is not getting significantly warmer due to human activities.

The point was that jack walter cites the science when it agrees with his position, but discounts it when it does not. (Nor does it address the problems in Hellner's article.)

Scientific Consensus: Earth's Climate Is Warming. For instance, the U.S. National Academy of Sciences says, "Scientists have known for some time, from multiple lines of evidence, that humans are changing Earth’s climate, primarily through greenhouse gas emissions." Certainly our position is well within the mainstream of scientific understanding.

Sure, the consensus could be wrong, but the contrarians have not provided substantial evidence that the consensus is wrong. We'd be happy to consider any evidence that you think argues otherwise.

ruralcounsel: First, true science isn't done by consensus.

Science is largely done by challenging the existing consensus. However, an appeal to authority can be a valid inductive argument based on the observation that experts speaking to a consensus in a field of study are more likely (but not certain) to be correct than non-experts. For instance, Einstein didn't directly confirm that the velocity of light was independent on the motion of the observer. That experimental result was outside his area of expertise. The decidedly non-intuitive effect was confirmed by Michelson & Morley and other observers. Einstein relied on this finding to devise his Special Theory of Relativity.

ruralcounsel: Second, no data provides any evidence that the warming is anthropogenic.

That in incorrect. The greenhouse effect is fundamental to the science of heat and energy. Without it, the Earth's oceans would be frozen. If you increase the concentration of atmospheric greenhouse gases, the Earth's surface will tend to warm, which has been known for over a century. 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.

ruralcounsel: The amount of CO2 we currently have is saturated with respect to the greenhouse effect.

While CO2’s strongest absorption at 15μm will have little effect on future warming, areas of the spectrum on either side of 15μm and other weaker bands will contribute to a stronger greenhouse effect as the concentration of atmospheric CO2 increases.

ruralcounsel: You could double the amount of CO2, and it would NOT double the greenhouse effect we currently are experiencing.

That’s correct. A doubling of atmospheric CO2, ignoring forcings, will lead to an increase in the greenhouse effect sufficient to raise the Earth’s surface temperatures by about 1°C, or about 3% of the current greenhouse effect.

ruralcounsel: The amount of greenhouse heating from CO2 is about 98+% of the maximum it could ever achieve.

The relationship is logarithmic, so there is no defined upper limit.

But we don’t have to guess. It wasn’t much of a surprise, as the physics are well understood, but direct observations confirm the theoretical prediction. See Feldman et al., Observational determination of surface radiative forcing by CO2 from 2000 to 2010, Nature 2015.

In case you're interested:

Z: The relationship is logarithmic, so there is no defined upper limit.

Logarithmic is approximate, of course. As CO2 increases to relatively high levels, the greenhouse effect actually increases somewhat faster than the logarithmic. See Zhong & Haigh, The greenhouse effect and carbon dioxide, Journal of the Royal Meteorological Society 2013: "Here we show in detail how, although the very centre of the 15μm band does become saturated, greenhouse trapping by CO2 at other wavelengths is far from saturation and that, as its concentration exceeds approximately 800ppmv, its effect actually increases at a rate faster than logarithmic."

Z: direct observations confirm the theoretical prediction

Here's the 'telescope' used to confirm that as CO2 increases, the radiative forcing of CO2 also increases.

What could a little out-of-the-way country few can find on the map have to do with American security?

Refusing to help defend allies would break a solemn promise made by the United States, a treaty ratified as the supreme Law of the Land by the United States Congress. Encouraging the war against sovereign nations by aggressive powers is heinous and reprehensible.

Lord Heathen: OK. I'll play. Hyperbole: Google it.

As Google confirms, hyperbole is a rhetorical device. As such, it only works if the listener gleans the actual meaning. However, Trump claims he told this to a European leader, apparently in all seriousness. It means the European leader could not be sure of American commitment to mutual defense.