Bad news for the climate change alarmists

Fritz Cahrenholt ande Rolf Dubal have a new paper "Radiative Energy Flux Variation from 2001-2020".  Here is the link.

The paper shows that changes in cloud mays explain most of the warming over this period and that little of it may be due to the "greenhouse effect", which implies that anthropogenic causes are much less than what is implied by the latest climate models.

In any case, climate science is not up to the task the alarmists assume.  It is likely that it is they who are the deniers.

Here are some excerpts.

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Abstract:

Radiative energy flux data, downloaded from CERES, are evaluated with respect to their
variations from 2001 to 2020. We found the declining outgoing shortwave radiation to be the most
important contributor for a positive TOA (top of the atmosphere) net flux of 0.8 W/m2 in this time
frame. We compare clear sky with cloudy areas and find that changes in the cloud structure should
be the root cause for the shortwave trend. The radiative flux data are compared with ocean heat
content data and analyzed in the context of a longer‐term climate system enthalpy estimation going
back to the year 1750. We also report differences in the trends for the Northern and Southern hemisphere. The radiative data indicate more variability in the North and higher stability in the South.
The drop of cloudiness around the millennium by about 1.5% has certainly fostered the positive net
radiative flux. The declining TOA SW (out) is the major heating cause (+1.42 W/m2 from 2001 to
2020). It is almost compensated by the growing chilling TOA LW (out) (−1.1 W/m2). This leads together with a reduced incoming solar of −0.17 W/m2 to a small growth of imbalance of 0.15 W/m2.
We further present surface flux data which support the strong influence of the cloud cover on the
radiative budget.

1. Introduction

In the big picture, climate variations originate from variations of the radiative balance
at the top of atmosphere (TOA). Surpluses of the EEI (Earth energy imbalance) or net
radiative energy fluxes, as measured by satellite mounted radiometers, lead to an increase
of the climate system enthalpy and vice versa [1–4]. For about two decades, the CERES
Energy Balanced and Filled (EBAF) Ed4.1 [5,6] offers datasets for a variety of radiative
fluxes, and, thus, provides a basis to scrutinize the radiative climate driving forces and
shine light on the cause‐and‐effect relation between radiation and temperature change.

As an independent but less direct source of information of the climate system enthalpy
change, there are several studies and reconstructions [7–12] of the ocean heat content
(OHC) which represents the bulk of the climate system enthalpy, estimated to be
about 90%. Assuming this fraction of 90% were a longer‐term constant, one can trace back
the time‐development of the climate system enthalpy. Von Schuckmann et al. [13] have
combined radiative, ocean heat and other data to reconstruct an enthalpy curve back to
1960 and have found an accelerated heating since 2010. Recently, Loeb et al. [14] found a
good agreement between radiative (CERES) and OHC data for the period mid‐2005 to
mid‐2019. These authors have further studied the influencing factors for the shortwave
(SW) and longwave (LW) radiative fluxes and concluded that cloud changes have fostered
the downwelling shortwave radiation.

Dewitte et al. [15] have analyzed CERES datasets for the period from 2000 to 2018
and found an EEI value of about 0.9 W/m2 but with a declining trend going in line with a
declining time‐derivative of the latest OHC data obtained from Cheng et al. [9]. Based
upon recent CERES data, Loeb et al. [16], Wong et al. [17] and Ollila [18] reported an increasing
downwelling shortwave (SW) radiation. Loeb et al. reported a decreasing TOA
SW trend, mainly caused by a reduction in low cloud cover, and Ollila concluded that this
increasing downwelling SW, which is particularly strong since 2014, may be responsible
for a new wave of heating after the hiatus. This finding is in conflict with the assumption
that further global warming originates mainly from the LW radiation capture caused by
greenhouse gases, i.e., a decline of outgoing LW.

The obvious and substantial, if not overwhelming role of clouds for the radiation
budget and climate system enthalpy and, hence, for the question about the root cause of
the further development of global warming, is nowadays still a vaguely known factor.
The cloud‐albedo feedback is deemed to be essential for climate modeling [19] but is still
poorly understood. According to a cloudiness dataset from EUMETSAT/CM SAF [20]
there was a significant drop in global cloudiness around the year 2000, which has not yet
fully recovered, and which certainly has affected the radiative net flux in the time‐period
considered here. In this paper, we report radiative flux data and trends in cloudy and
cloud‐free regions, obtained from CERES and other sources and relate them to the TOA
and surface radiative budgets and climate system enthalpy. We further attribute the differences
between the Northern and the Southern hemisphere.

Finally, we discuss these results in a longer‐term context and suggest a possible correlation
of cloud cover shifts such as the one around the millennium with the AMO (Atlantic
Multidecadal Oscillation).

6. Conclusions

Radiative energy flux data from CERES were analyzed and showed in accordance
with OHC data a further increasing climate system enthalpy during the period 2001–2020.
The total enthalpy rise amounted to about 240 ZJ in these two decades. As Figure 15
shows, the major driving effect was the declining shortwave TOA emission. The TOA
outgoing longwave emission has increased and therefore reduced the TOA net flux.

Generating the CERES data is a demanding task and requires sophisticated technology
and models which are vulnerable and prone to uncertainties. Liu et al. [28] have
pointed out significant uncertainties of satellite datasets and discussed the role of the lateral
energy flow. Su et al. [29] have recently pointed out the importance of maintaining
the consistency among the components of the measuring system. On the other hand, Loeb
et al. [14], Johnson et al. [30] and, also, Dewitte et al. [15] have shown that the CERES net
flux agrees well with the independently observed OHC data. This good agreement, also
confirmed by our analysis, justifies some confidence in the CERES datasets used.

We could identify the effect of the anthropogenic greenhouse gas emissions from
2001 to 2020 in the “Clear Sky” LW part but not in the “Cloudy Areas” and not in the SW.
At the same time, we find, in accordance with the analysis of Loeb et al. [14] and Ollila
[18], that the major changes for the TOA energy budget during this period of time
stemmed from the clouds for SW and LW, as well as the ground temperature in the LW.

Loeb et al. [14] pointed out, that the direct aerosol effect is rather small, but the indirect
effect via the cloud formation may be larger. The shift from a negative to a positive
PDO (Pacific Decadal Oscillation) index as an additional factor for the net TOA flux is
mentioned in [14].

Our analysis, which differentiates between clear sky and cloudy areas, support that
in view of the historical heating steps shown in Figure 13, that the currently observed high
radiative net flux has a large intrinsic component. As shown in Figure 13, the heating

phases coincide with the AMO change from negative to positive. It has been shown by

several authors that AMO may be an important intrinsic climate factor [31–33]. A similar

discussion was held about 20 years ago in papers of Chen et al. [34] and Wielicki et al.

[35], both of them emphasized the underestimated decadal natural variabilities in the

tropical regions.

The start‐to‐end bridge charts in Figures 15 (TOA) and 16 (surface) are highlighting

the effect of the “Cloudy Areas” and the shortwave radiation in a slightly different view.

In these figures, we look at the actual start and end data, their actual differences from 2001

to 2020, and the actual incremental contribution of each of the radiative categories. Please

note, that the increments are weighted by area. In Figure 15 (TOA), the biggest changes

originate from the “Cloudy Areas”. In Figure 16 (surface) the largest heating impulse

stemmed from the increasing downwelling and decreasing upwelling shortwave fluxes

in the “Cloudy Areas” (together +1.23 W/m2), the strongest cooling effect was the decreased

longwave downwelling flux in the “Cloudy Areas” (−1.48 W/m2), followed by increasing

LW upwelling fluxes in the “Cloudy Areas” (−1.34 W/m2) and the “Clear Sky”

(−0.93 W/m2). The change of the longwave downwelling radiation can be interpreted in

part as the additional effect of the increased greenhouse gas concentration. For the “Clear

Sky” it is +1.20 W/m2. In the “Cloudy Areas”, this effect is negative (−1.48 W/m2) so that

the sum of these values is −0.14 W/m2. The −0.93 W/m2 of the “Clear Sky” upwelling

longwave should be caused by the increased thermal emission due to the higher surface

temperature.

There are distinct differences between the Northern and the Southern hemisphere.

Generally speaking, the South was more stable than the North in trends and variances of

almost all radiative quantities. This could be due to the larger ocean share of the surface

in the South.

Finally, the key issue, i.e., whether the current heating phase is a temporary phase or

a permanent phenomenon, can be judged only on the basis of a longer observation time.

In the latter case, the physical mechanism behind the “shortwave heating” [18] or a possible

“cloud thinning”, as discussed by several other authors [36–38] should be understood,

because it could accelerate the warming trend. In the former case, the strong net

flux of +0.8 W/m2 should decrease naturally.