Atmospheric Gases: When discussing atmospheric gases, it is useful to refresh one’s memory of the relative concentrations of various gases. To be more useful these will be put in the same units, that is ppmv: parts per million by volume. In the idealized dry atmosphere:
Nitrogen is about 78% of the atmosphere or 780,840 ppmv;
Oxygen is 20.9% or 209,460 ppmv;
Argon is 0.93% of the atmosphere or 9,340 ppmv;
Carbon dioxide is about 0.04% of the atmosphere or 400 ppmv [carbon dioxide varies seasonally and is increasing]. The next greenhouse gas, significantly lower, is
Methane, with about 0.00018% of the atmosphere or 1.79 ppmv;
Nitrous oxide is about 0.0000325% or 0.325 ppmv; and
Ozone is about 0 to 0.000007% or 0 to 0.07 ppmv.
The greenhouse influence of ozone is predominantly in the upper the atmosphere, the stratosphere, where it is created naturally by chemical reactions involving solar ultraviolet…
An observed decline of surface shortwave radiation (SSR) in Europe discovered from about 1950s until about the 1980s and many parts of the world is attributed to increasing emissions of anthropogenic aerosols (dimming phase). The followed increase of SSR in some regions (brightening phase) is a consequence of the clean air business in Europe.
The simulations with detailed treatment of aerosols and their interaction with clouds are needed for understanding the regional SSR trends. The NASA GISS ModelE2 is used in this study. It is based on transient simulations with natural and anthropogenic forcings.
We compare two simulations with transient aerosol emissions with the focus on aerosol effects on clouds. For the annual mean SSR, the dimming trends range between -4.4 W/m2 over the Mediterranean region and -1.7 W/m2 over the middle Europe. Brightening trends range from…
Over the last twenty years there has been good progress in understanding the solar influence on climate. In particular, many scientific studies have shown that changes in solar activity have impacted climate over the whole Holocene period (approximately the last 10,000 years). A well-known example is the existence of high solar activity during the Medieval Warm Period, around the year 1000 AD, and the subsequent low levels of solar activity during the cold period, now called The Little Ice Age (1300–1850 AD).
An important scientific task has been to quantify the solar impact on climate, and it has been found that over the eleven-year solar cycle the energy that enters the Earth’s system is of the order of 1.0–1.5 W/m2. This is nearly an order of magnitude larger than what would be expected from solar irradiance alone, and suggests that solar activity is getting amplified by some atmospheric process.
Three main theories have been put forward to explain the solar–climate link, which are:
solar ultraviolet changes
the atmospheric-electric-field effect on cloud cover
cloud changes produced by solar-modulated galactic cosmic rays (energetic particles originating from inter stellar space and ending in our atmosphere).
Significant effort has gone into understanding possible mechanisms, and at the moment cosmic ray modulation of Earth’s cloud cover seems rather promising in explaining the size of solar impact.
This theory suggests that solar activity has had a significant impact on climate during the Holocene period. This understanding is in contrast to the official consensus from the Intergovernmental Panel on Climate Change, where it is estimated that the change in solar radiative forcing between 1750 and 2011 was around 0.05 W/m2, a value which is entirely negligible relative to the effect of greenhouse gases, estimated at around 2.3 W/m2. However, the existence of an atmospheric solar-amplification mechanism would have implications for the estimated climate sensitivity to carbon dioxide, suggesting that it is much lower than currently thought.
In summary, the impact of solar activity on climate is much larger than the official consensus suggests. This is therefore an important scientific question that needs to be addressed by the scientific community.
SUMMARY:Evidence is presented that an over-correction of satellite altimeter data for increasing water vapor might be at least partly responsible for the claimed “acceleration” of recent sea level rise.
I have been thinking about an issue for years that might have an impact on what many consider to be a standing disagreement between satellite altimeter estimates of sea level versus tide gauges.
Since 1993 when satellite altimeter data began to be included in sea level measurements, there has been some evidence that the satellites are measuring a more rapid rise than the in situ tide gauges are. This has led to the widespread belief that global-average sea level rise — which has existed since before humans could be blamed — is accelerating.
I have been the U.S. Science Team Leader for the Advanced Microwave Scanning Radiometer (AMSR-E) flying on NASA’s Aqua satellite. The water vapor retrievals from that instrument use algorithms similar to those used by the altimeter people.
I have a good understanding of the water vapor retrievals and the assumptions that go into them. But I have only a cursory understanding of how the altimeter measurements are affected by water vapor. I think it goes like this: as tropospheric water vapor increases, it increases the apparent path distance to the ocean surface as measured by the altimeter, which would cause a low bias in sea level if not corrected for.
What this potentially means is that *if* the oceanic water vapor trends since 1993 have been overestimated, too large of a correction would have been applied to the altimeter data, artificially exaggerating sea level trends during the satellite era.
What follows probably raises more questions that it answers. I am not an expert in satellite altimeters, I don’t know all of the altimeter publications, and this issue might have already been examined and found to be not an issue. I am merely raising a question that I still haven’t seen addressed in a few of the altimeter papers I’ve looked at.
Why Would Satellite Water Vapor Measurements be Biased?
The retrieval of total precipitable water vapor (TPW) over the oceans is generally considered to be one of the most accurate retrievals from satellite passive microwave radiometers.
Water vapor over the ocean presents a large radiometric signal at certain microwave frequencies. Basically, against a partially reflective ocean background (which is then radiometrically cold), water vapor produces brightness temperature (Tb) warming near the 22.235 GHz water vapor absorption line. When differenced with the brightness temperatures at a nearby frequency (say, 18 GHz), ocean surface roughness and cloud water effects on both frequencies roughly cancel out, leaving a pretty good signal of the total water vapor in the atmosphere.
What isn’t generally discussed, though, is that the accuracy of the water vapor retrieval depends upon the temperature, and thus vertical distribution, of the water vapor. Because the Tb measurements represent thermal emission by the water vapor, and the temperature of the water vapor can vary several tens of degrees C from the warm atmospheric boundary layer (where most vapor resides) to the cold upper troposphere (where little vapor resides), this means you could have two slightly different vertical profiles of water vapor producing different water vapor retrievals, even when the TPW in both cases was exactly the same.
The vapor retrievals, either explicitly or implicitly, assume a vertical profile of water vapor by using radiosonde (weather balloon) data from various geographic regions to provide climatological average estimates for that vertical distribution. The result is that the satellite retrievals, at least in the climatological mean over some period of time, produce very accurate water vapor estimates for warm tropical air masses and cold, high latitude air masses.
But what happens when both the tropics and the high latitudes warm? How do the vertical profiles of humidity change? To my knowledge, this is largely unknown. The retrievals used in the altimeter sea level estimates, as far as I know, assume a constant profile shape of water vapor content as the oceans have slowly warmed over recent decades.
Evidence of Spurious Trends in Satellite TPW and Sea Level Retrievals
For many years I have been concerned that the trends in TPW over the oceans have been rising faster than sea surface temperatures suggest they should be based upon an assumption of constant relative humidity (RH). I emailed my friend Frank Wentz and Remote Sensing Systems (RSS) a couple years ago asking about this, but he never responded (to be fair, sometimes I don’t respond to emails, either.)
For example, note the markedly different trends implied by the RSS water vapor retrievals versus the ERA Reanalysis in a paper published in 2018:
The upward trend in the satellite water vapor retrieval (RSS) is considerably larger than in the ERA reanalysis of all global meteorological data. If there is a spurious component of the RSS upward trend, it suggests there will also be a spurious component to the sea level rise from altimeters due to over-correction for water vapor.
Now look at the geographical distribution of sea level trends from the satellite altimeters from 1993 through 2015 (published in 2018) compared to the retrieved water vapor amounts for exactly the same period I computed from RSS Version 7 TPW data:
There is considerably similarity to the patterns, which is evidence (though not conclusive) for remaining cross-talk between water vapor and the retrieval of sea level. (I would expect such a pattern if the upper plot was sea surface temperature, but not for the total, deep-layer warming of the oceans, which is what primarily drives the steric component of sea level rise).
Further evidence that something might be amiss in the altimeter retrievals of sea level is the fact that global-average sea level goes down during La Nina (when vapor amounts also go down) and rise during El Nino (when water vapor also rises). While some portion of this could be real, it seems unrealistic to me that as much as ~15 mm of globally-averaged sea level rise could occur in only 2 years going from La Nina to El Nino conditions (figure adapted from here) :
Especially since we know that increased atmospheric water vapor occurs during El Nino, and that extra water must come mostly from the ocean…yet the satellite altimeters suggest the oceans riserather than fall during El Nino?
The altimeter-diagnosed rise during El Nino can’t be steric, either. As I recall (e.g. Fig. 3b here), the vertically integrated deep-ocean average temperature remains essentially unchanged during El Nino (warming in the top 100 m is matched by cooling in the next 200 m layer, globally-averaged), so the effect can’t be driven by thermal expansion.
Finally, I’d like to point out that the change in the shape of the vertical profile of water vapor that would cause this to happen is consistent with our finding of little to no tropical “hot-spot” in the tropical mid-troposphere: most of the increase in water vapor would be near the surface (and thus at a higher temperature), but less of an increase in vapor as you progress upward through the troposphere. (The hotspot in climate models is known to be correlated with more water vapor increase in the free-troposphere).
Again, I want to emphasize this is just something I’ve been mulling over for a few years. I don’t have the time to dig into it. But I hope someone else will look into the issue more fully and determine whether spurious trends in satellite water vapor retrievals might be causing spurious trends in altimeter-based sea level retrievals.
In the 1990s, solar physicists, Penn and Livingston, called for a long decline in solar activity. This is the case and it is nice to see such work confirmed by events. Solar Cycles # 23 and 24 are the weakest since the early 1900s. The current run of consecutive Spotless Days is out to 33, or 75%, for the year.
The following table shows the record back to the minimum of Solar Cycle # 23 when the count was at 268 days, or 73%, for 2008.
So far this year, the count is out to 33 consecutive days, which is exceptional. So much so, that SILSO keeps a table of such long runs.
Solar Cycle # 24 is expected to reach its minimum by late in this year.
For hundreds of millions of years such changes in solar activity have been associated with changes from warming to cooling. And back again. The long run to the recent peak in activity was the strongest in thousands of years. Despite this, temperatures were not as warm for as long as set during the Medieval Warm Period. The end to that long trend and turn to cooling in the early 1300s was drastic, causing widespread crop failures and famine in Northern Europe and England. A book by William Rosen, “The Third Horseman” covers it thoroughly. The die-off from 1315 to 1320 is estimated at some 10 percent of the population. Deaths of cattle, sheep and horses were severe as well. All due to the turn to cold and unusually wet weather.
The change to what some are calling the Modern Minimum is significant. In geological perspective, it is now a built-in cooling force.
The next chart shows that the satellite record is again approaching the flat-lying trend, which is out to some 20 years. The El Ninos of 1998 and 2016 were distinctive weather- warming events.
NOAA’s Winter Forecast made on October 18th has been wrong on temperature and precipitation. North America has suffered a cold, snowy and lengthy winter, beyond what could be blamed upon the demon “Polar Vortex”.
Over time, diminishing solar activity has been likely to be accompanied by more cosmic rays and more cloud cover. Which would be associated with cooler and snowier winters. And possibly cooler summers, which the Danish Met Institute reported for 2018 and 2017.
Discussions and arguments concerning global warming/climate change often get into the issue of discerning the longer term signal within the shorter term noisy temperature records. The effort to separate natural and human forcings of estimated Global Mean Temperatures reminds of the medieval quest for the Holy Grail. Skeptics of CO2 obsession have also addressed this. For example the graph above from Dr. Syun Akasofu shows a quasi-60 year oscillation on top of a steady rise since the end of the Little Ice Age (LIA). Various other studies have produced similar graphs with the main distinction being alarmists/activists attributing the linear rise to increasing atmospheric CO2 rather than to natural causes (e.g. ocean warming causing the rising CO2).
I’ve received many more requests about the new disappearing-clouds study than the “gold standard proof of anthropogenic warming” study I addressed here, both of which appeared in Nature journals over the last several days.
The widespread interest is partly because of the way the study is dramatized in the media. For example, check out this headline, “A World Without Clouds“, and the study’s forecast of 12 deg. C of global warming.
The disappearing clouds study is based upon the modelling of marine stratocumulus clouds, whose existence substantially cools the Earth. These extensive but shallow cloud decks cover the subtropical ocean regions over the eastern ocean basins where upwelling cold water creates a strong boundary layer inversion.
In other words, the cold water causes a thin marine boundary layer of chilled air up to a kilometer deep, than is capped by warmer air aloft. The resulting inversion layer (the boundary between cool air below and warm air aloft) inhibits convective mixing, and so water evaporated from the ocean accumulates in the boundary layer and clouds then develop at the base of the inversion. There are complex infrared radiative processes which also help maintain the cloud layer.
The new modeling study describes how these cloud layers could dissipate if atmospheric CO2 concentrations get too high, thus causing a positive feedback loop on warming and greatly increasing future global temperatures, even beyond what the IPCC has predicted from global climate models. The marine stratocumulus cloud response to warming is not a new issue, as modelers have been debating for decades whether these clouds would increase or decrease with warming, thus either reducing or amplifying the small amount of direct radiative warming from increasing CO2.
The new study uses a very high resolution model that “grows” the marine stratocumulus clouds. The IPCC’s climate models, in contrast, have much lower resolution and must parameterize the existence of the clouds based upon larger-scale model variables. These high resolution models have been around for many years, but this study tries to specifically address how increasing CO2 in the whole atmosphere changes this thin, but important, cloud layer.
The main conclusion of the study is that when model CO2 concentrations reach 1200 ppm or so (which would take as little as another 100 years or so assuming worst-case energy use and population growth projections like RCP8.5), a substantial dissipation of these clouds occurs causing substantial additional global warming, with up to 12 deg. C of total global warming.
Shortcomings in the Study: The Large-Scale Ocean and Atmospheric Environment
All studies like this require assumptions. In my view, the problem is not with the high-resolution model of the clouds itself. Instead, it’s the assumed state of the large-scale environment in which the clouds are assumed to be embedded.
Most importantly, it should be remembered that these clouds exist where cold water is upwelling from the deep ocean, where it has resided for centuries to millennia after initially being chilled to near-freezing in polar regions, and flowing in from higher latitudes. This cold water is continually feeding the stratocumulus zones, helping to maintain the strong temperature inversion at the top of the chilled marine boundary layer. Instead, their model has 1 meter thick slab ocean that rapidly responds to only whats going on with atmospheric greenhouse gases within the tiny (5 km) model domain. Such a shallow ocean layer would be ok (as they claim) IF the ocean portion of the model was a closed system… the shallow ocean only increases how rapidly the model responds… not its final equilibrium state. But given the continuous influx of cold water into these stratocumulus regions from below and from high latitudes in nature, it is far from a closed system.
Second, the atmospheric environment in which the high-res cloud model is embedded is assumed to have similar characteristics to what climate models produce. This includes substantial increases in free-tropospheric water vapor, keeping constant relative humidity throughout the troposphere. In climate models, the enhanced infrared effects of this absolute increase in water vapor leads to a tropical “hot spot”, which observations, so far, fail to show. This is a second reason the study’s results are exaggerated. Part of the disappearing cloud effect in their model is from increased downwelling radiation from the free troposphere as CO2 increases and positive water vapor feedback in the global climate models increases downwelling IR even more. This reduces the rate of infrared cooling by the cloud tops, which is one process that normally maintains them. The model clouds then disappear, causing more sunlight to flood in and warm the isolated shallow slab ocean. But if the free troposphere above the cloud does not produce nearly as large an effect from increasing water vapor, the clouds will not show such a dramatic effect.
The bottom line is that marine stratocumulus clouds exist because of the strong temperature inversion maintained by cold water from upwelling and transport from high latitudes. That chilled boundary layer air bumps up against warm free-tropospheric air (warmed, in turn, by subsidence forced by moist air ascent in precipitation systems possibly thousands of miles away). That inversion will likely be well-maintained in a warming world, thus maintaining the cloud deck, and not causing catastrophic global warming.
This dialogue framework was proposed for a debate between William Happer and David Karoly sponsored by The Best Schools. As you can see it reads like an high hurdle course for alarmists/activists. There are significant objections at every leap in connecting the beliefs.
Earth does better with more CO2. CO2 levels are increasing
Atmospheric transmission of radiation: Tyndall correctly recognized in 1861 that the most important greenhouse gas of the Earth’s atmosphere is water vapor. CO2 was a modest supporting actor, then as now.
Radiative cooling of the Earth: Clouds are one of the most potent factors controlling Earth’ s surface temperature.
The Schwarzschild equation: The observed intensity I of upwelling radiation comes from the radiation emitted by the surface and by greenhouse gases in the atmosphere above the surface. The rate of change of the intensity with altitude…