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Radiative energy flux variations from 2000 2020 – Watts Up With That?



Reposted from Dr. Judith Curry’s Climate Etc.

by Fritz Vahrenholt and Rolf Dubal

The warming of the last 20 years has its essential cause in the change of the clouds.

We have investigated the Earths radiation balance over the last 20 years in a peer reviewed publication in Atmosphere. The net radiation flux, i.e. the difference between solar irradiation and long- and short-wave radiation, determines the change in the energy content of the climate system. If it is positive, the Earth is heating up; if it is negative, it means cooling. The NASA-operated satellite-based CERES project has been providing such radiation data for two decades now, as well as data on the development of cloud cover in temporal and spatial resolution. These data are determined both in relation to an altitude of approx. 20 km (TOA = Top of Atmosphere), and also in relation to the Earths surface.

Our new publication Radiative Energy flux variation from 2001 2020 has brought to light a surprising result for climate science: the warming of the Earth in the last 20 years is mainly due to a higher permeability of clouds for short-wave solar radiation. Short-wave radiation has decreased sharply over this period (see figure), equally in the northern and southern hemispheres (NH and SH). With solar radiation remaining nearly constant, this means that more shortwave radiation has reached the Earths surface, contributing to warming. The long-wave back radiation (the so-called greenhouse effect) contributed only to a lesser extent to the warming. It was even largely compensated for by the likewise increasing permeability of the clouds to long-wave radiation emanating from the Earth. The authors come to this clear conclusion after evaluating the CERES radiation data.

NASA researcher Norman Loeb and collaborators [link], as well as the Finnish researcher Antero Ollila [link], had already recently pointed out that the short-wave solar radiation increased from 2005 to 2019 due to the decrease in low clouds. Our latest publication has examined TOA and ground-level radiation fluxes for the entire period and related them to changes in cloud cover. The net energy influx was positive throughout the period, increasing from 0.6 W/m to 0.75 W/m from 2001 to 2020. The 20-year average was 0.8 W/m. The bridge chart shows the drivers of this change and these are clearly in the area of shortwave radiation in the cloudy areas, which make up about 2/3 of the Earths surface (SW Cloudy Area, +1.27 W/m).

This contrasts with the assumption made by the IPCC in its most recent report that the warming caused by the increase in long-wave back radiation was due solely to the anthropogenic greenhouse effect. The IPCC attributes 100% of the warming to this effect and justifies this with model calculations. However, the analysis of the measured data by Dbal and Vahrenholt shows that the warming due to the decrease of 1.4 W/m short-wave radiation and the 1.1 W/m increase in long-wave radiation is mainly attributable to the cloud effect.

We also considered the effect of this radiative excess on the heat content of the climate system for a longer period since 1750, where enthalpy means the sum of heat, work and the latent heat, i.e. heat of evaporation of water, heat of melting of ice, energetic change of the biosphere (plant growth), etc. Since about 90% of this enthalpy remains as heat in the oceans, conclusions about enthalpy development can also be drawn by looking at long-term ocean heat content (OHC). Good agreement was found between these two independent data sets for the period 2001-2020, and existing OHC data were evaluated for earlier, longer periods to provide an overall picture. This shows that warming since 1750 has not been continuous, but has occurred in heating episodes, designated A, B and C, during each of which a high net radiative flux (0.7 to 0.8 W/m) acted for 20-30 years, interspersed with milder phases. The onset of these heating episodes coincided with the change of sign of another known natural climate factor, the AMO (Atlantic Multidecadal Oscillation). The crucial question of whether the present heating phase C will soon come to an end as in cases A and B, or whether it will continue, can only be decided on the basis of longer observations and must therefore remain open.

In order to investigate the beginning of phase C around the year 2000, further data sets were used, including the cloudiness measurements of EUMETSAT, a European satellite project. Here it can be seen that the onset of phase C is accompanied by a decrease in cloudiness, coinciding with the above-mentioned change in sign of the AMO. From the radiation measurements it can be deduced that 2% less cloud cover means about 0.5 W/m more net radiation flux, which could explain most of the 0.8 W/m mentioned above.

This result is also corroborated by the analysis of the near-surface radiation balance. Here an increase of the greenhouse effect is found, which correlates well with the increase of the greenhouse gases water vapour and CO2, but only for the cloudless areas (clear sky). This correlation, however, does not apply to the cloud-covered areas, which make up about 2/3 of the earth.

We could prove the increased greenhouse effect of the sum of all greenhouse gases (water vapour, CO2 etc.) under Clear Sky conditions with 1.2 W/m increase in the last 20 years. However, this increase is overcompensated on an area-weighted basis by the increasing radiation of long-wave radiation in the cloudy zones (Cloudy Areas) amounting to -1.48 W/m.

The time span of 20 years is still too short to be able to decide conclusively whether the current heating phase is a temporary or permanent development. In the former case, climate forecasts will have to be fundamentally revised. The physical mechanism that led to the cloud thinning is discussed differently in the literature. Vahrenholt: The cloud changes can be caused by a decrease in aerosols, by atmospheric warming due to natural causes (e.g. the AMO or the PDO), by anthropogenic warming due to CO2, or by a combination of these individual factors. However, one thing can already be stated: the warming of the last 20 years has been caused more by change in the clouds than by the classical greenhouse effect.

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Weather vs. Alarmism – Watts Up With That?



Brief Note by Kip Hansen — 20 October 2021

Channel 4, a British free-to-air public-service television network, sent a three-person TV crew to the Heartland Institutes’ 14th International Conference on Climate Change held this last weekend in Las Vegas, Nevada. I met and spoke with the two journalists. It took me less than ten seconds to realize that they had been sent to gather material for a scurrilous hit job piece on the conference. And that is exactly what they did.

The news clip (well, really just bit of video-climate-alarmism masquerading as journalism) exposes the featured Channel 4 reporter when, instead of asking questions and reporting the answers, her role is shown to be arguing for the alarmist viewpoint on camera.

I only mention this because the Smoking Gun of Climate Disaster in the broadcast news clip was Lake Mead, with its lowest water level “ever”.

The weather almost never co-operates . . . ask any sailor.

Atmospheric river storms to soak Bay Area, Northern California biggest in 9 months

“Three successive storms will surge in from the Pacific Ocean this week, forecasters said Tuesday, bringing what may be the most rain in nine months to drought-stricken Northern California and offering a promising start to winter after two years marked by record wildfires and dry conditions.

Two of those storms look like atmospheric rivers narrow, moisture-rich storms that play a critical role in the states water supply. The first, which was set to arrive late Tuesday night and continue into Wednesday morning, is likely to be a moderate storm. But another big one shaping up for Sunday night was upgraded to a category 5 on Tuesday, the highest in a five-level scale.

On average Northern California might get 1 or 2 of those a year, said Marty Ralph, director of the Center for Western Weather and Water Extremes at UC San Diego. We are looking at prolonged rain and some heavy rain.

The storms will dramatically reduce fire danger across Northern California, possibly all but ending it in some places. But they could also cause a risk of mudslides in some burned areas, particularly the Dixie Fire near Mount Lassen and the Caldor Fire near South Lake Tahoe.”

The last time California and the American Southwest had such an event was January 2021.

This new series of storms are predicted to drop up to two feet of snow in the high Sierras. 2017, which was the wettest year on record in much of California, also began with a series of similar soaking storms soaking in October. The incoming storms are predicted to be so serious, bring so much water and snow, that CalTrans has closed Highway 1 through the Big Sur area.

The weather is on our side and will help to debunk the Channel 4 nonsense.

This one series of three or four storms will not, of course, refill Lake Mead to historic levels, but a they are a good start to a wet winter for the parched and fire-scarred American West.

# # # # #

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2001-2019 Warming Driven By Increases In Absorbed Solar Radiation, Not Human Emissions – Watts Up With That?



Reposted from the NoTricksZone

ByKenneth Richardon18. October 2021

Three new studies affirm the increase in absorbed solar radiation associated with decreased reflection by clouds (albedo) has been the root cause of the positive Earth Energy Imbalance and global warming since the early 2000s.

Scientists (Loeb et al., 2021) have determined the rather uncertain positive trend in Earths Energy Imbalance (EEI) from 2005 to 2019, 0.5 W/m 0.47 W/m per decade1, is primarily due to an increase in absorbed solar radiation associated with decreased reflection by clouds.

CERES satellite data indicate clouds and surface albedo account for 89% of the absorbed solar radiation trend in the 21st century, whereas anthropogenic greenhouse gases account for but a tiny fraction of the trends in combined absorbed solar radiation and greenhouse effect forcing (reductions in emitted thermal radiation) during this period.

This very small human emissions/greenhouse gas impact is represented by the red Other (trace gases) bars in the graph below. In emitted thermal radiation, graph (e) shows the greenhouse gas impact is effectively offset by the cloud influence; both factors are cancelled out by temperature changes. This leaves the increase in absorbed solar radiation shown in graph (d) due to natural variations in clouds and surface albedo (SFC) as the primary driver(s) of top-of-atmosphere (TOA) flux forcing during the last two decades.

Image Source: Loeb et al., 2021

Other scientists (Dbal and Vahrenholt, 2021) have also concluded that the positive TOA net flux (+1.42 W/m) from increasing downwelling shortwave (SW) facilitated by a drop in cloudiness has been the major driving effect, dominating influence, and major heating cause explaining the 2001-2019 ocean heat content increase (240 ZJ).

The authors note these CERES satellite observations conflict with the assumption further global warming originates mainly from the LW [longwave] radiation capture caused by greenhouse gases, i.e., a decline in outgoing LW. In fact, the LW or greenhouse effect impact has been negative; it has contributed a net cooling influence (-1.1 W/m) over the last two decades.

Image Source: Dbal and Vahrenholt, 2021

The summarizing text from another new study (Ollila, 2021) bluntly asserts the substantial increase in downwelling SW radiation from 2000-2019 demonstrates there are natural climate drivers that have rapid and significant temperature impacts exceeding the anthropogenic drivers, and that any temperature increase since 2015-16 cannot be due to anthropogenic reasons.

Image Source: Ollila, 2021

These newer studies affirming the  21st increase in absorbed solar radiation has driven modern warming are further substantiated by a 2020 Nature journal paper (Delgado-Bonal et al., 2020) extending the positive (+3 W/m) cloud-albedo SW impact back to 1980.

[S]hortwave radiation is the main driver in the dynamics and plays a major role in the energy balance by affecting the longwave radiation field.
Our research supports the idea that clouds and albedo, which ultimately determine the SW radiation, are variables of the utmost importance for current climate change, in agreement with previous research about the changes in stratocumulus or energy imbalance in the last four decades for example. An increase in cloud coverage of 0.1 would, on average, lead to a 7% increase in spectrally integrated global average reflectance of shortwave radiation.
Image Source: Delgado-Bonal et al., 2020

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Weekly Climate and Energy News Roundup #475 – Watts Up With That?



The Week That Was: 2021-10-16 (October 16, 2021)
Brought to You by SEPP (
The Science and Environmental Policy Project


By Ken Haapala, President, Science and Environmental Policy Project (SEPP)

Presentation of the Fredrick Seitz Memorial Award: Comments Given at 14th International Conference on Climate Change by The Heartland Institute introducing David R. Legates, recipient of the 2021 Fredrick Seitz Memorial Award.

Physical Science develops with the constant conflict between ideas and evidence. What ideas best fit the physical evidence? When the physical evidence changes the ideas must change accordingly. Otherwise, the science becomes stagnant, dogmatic. That is what is happening to the science claimed by the UN Intergovernmental Panel on Climate Change (IPCC) and its followers, including many once noted US science institutions.

In 1988, the UN established the IPCC to (1) assess the scientific information related to changes in climate from emissions of greenhouse gases and 2) formulate realistic responses. The IPCC issued its first report in 1990. 

Since then, a great deal has changed including:

  1. human conditions have greatly improved thanks to the use of fossil fuels.
  • the physical evidence of what is happening in the atmosphere with increasing CO2 has greatly improved
  • the attitudes of Western governments to changing science have worsened

Over the last 30 years, one of the most remarkable changes is the tremendous reduction in people living in extreme poverty. Extreme poverty is defined as person having a local purchasing power of $1.90 a day. It is estimated in local currency and adjusted to inflation and similar issues. The estimates used here come from Our World In Data and were updated in 2019

As you see, 30 years ago 1.9 billion people 36% of the worlds population lived in extreme poverty, mostly in Asia. Extreme poverty is life on the edge of death. In 2018, 650 million lived on the edge, about 9% of the worlds population. The great reduction in those living in extreme poverty is despite an increase in population of about 43%.

From 1990 through 2018 the worlds CO2 emissions increased by 60%. Chinas CO2 emissions grew by 315%, more than three times. Today, Asia emits more CO2 than all other continents combined.


A second remarkable change is Space Age Technology which gives us the ability to observe and measure what is occurring in the atmosphere, where the greenhouse effect occurs. This evidence contradicts that early scientific speculation. Despite a 60% increase the influence of CO2 on global temperatures is modest, and not dangerous.


A third remarkable change is the obstinance of Western Governments and many western science institutions in ignoring the changing evidence. Contrary to the scientific method they are refusing to adjust their views, which they still call scientific, to the great expansion in physical evidence about the atmosphere and the effects of carbon dioxide. With mounting physical evidence, what began as a scientific speculation has drifted into world of science fiction and political myth.

Washington DC is a hotbed for science myths and attacking all who dare question them. Our honoree had already experienced what happens to physicists who challenge the accepted myths with physical evidence. In his experience in estimating precipitation, he always advocated those measurements must be checked and double checked, and when scientific concepts do not meet the evidence from experiments and observations, the concepts must be change. This winter, when given an opportunity he bravely stood up, and with the support of a few, declared certain myths popular in Washington are not science, and explained why.

Ladies and gentlemen, I have the privilege to present to you the honoree of the 2021 Fredrick Seitz Memorial Award, Dr. David Russell Legates


More details of the Heartland Conference will appear next week in a full TWTW

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