1,390 research outputs found
Climate Science: Is it currently designed to answer questions?
For a variety of inter-related cultural, organizational, and political
reasons, progress in climate science and the actual solution of scientific
problems in this field have moved at a much slower rate than would normally be
possible. Not all these factors are unique to climate science, but the heavy
influence of politics has served to amplify the role of the other factors. Such
factors as the change in the scientific paradigm from a dialectic opposition
between theory and observation to an emphasis on simulation and observational
programs, the inordinate growth of administration in universities and the
consequent increase in importance of grant overhead, and the hierarchical
nature of formal scientific organizations are cosidered. This paper will deal
with the origin of the cultural changes and with specific examples of the
operation and interaction of these factors. In particular, we will show how
political bodies act to control scientific institutions, how scientists adjust
both data and even theory to accommodate politically correct positions, and how
opposition to these positions is disposed of.Comment: 36 pages, no figures. v2: footnotes 16, 19, 20 added, footnote 17
changed, typos corrected. v3: description of John Holdren corrected, expanded
discussion of I=PAT formula, typos corrected. v4: The reference to Deming
(2005) added in v3 stated that a 1995 email in question was from Jonathan
Overpeck. In fact, Deming had left the sender of the email unnamed. The
revision v4 now omits the identification of Overpeck. However, the revision
v4 now includes a more recent and verifiable reference to a 2005 emai
Climate Forcing by the Volcanic Eruption of Mount Pinatubo. Revised edition
We determine the volcano climate sensitivity and response time for the Mount
Pinatubo eruption. This is achieved using observational measurements of the
temperature anomalies of the lower troposphere and the aerosol optical density
(AOD) in combination with a radiative forcing proxy for AOD. Using standard
linear response theory we find sensitivity = 0.18 +- 0.04 K/(W/m2), which
implies a negative feedback of -1.0 +- 0.4. The intrinsic response time is
5.8+-1.0 months. Both results are contrary to the conventional paradigm that
includes long response times and positive feedback. In addition, we analyze the
outgoing longwave radiation during the Pinatubo eruption and find that its time
dependence follows the forcing much more closely than the temperature, and even
has an amplitude equal to that of the AOD proxy. This finding is independent of
the response time and feedback results.Comment: 22 pages, including 4 figures. Revised version of a paper [Douglass
D. H. and R. S. Knox (2005), Climate forcing by the volcano eruption of Mount
Pinatubo. Geophys. Res. Lett. 32, L05710.doi: 10.1029/2004GL022119]. Revision
is based on subsequent comments and replies to appear in the same journal.
Quantitative results have only minor change
Globalne ocieplenie: przyczyny i natura domniemanego naukowego konsensusu
âGlobal warmingâ is perceived in the literate word as both real and dangerous. However many aspects of the catastrophic scenario have already been largely discounted by the scientific community. In this paper I shall review the science associated with global change, including lack of conformance of data from computer models with data taken from the satellite measures.âGlobalne ocieplenieâ jest obecnie postrzegane jako zjawisko zarĂłwno realne, jak i niebezpieczne. Zarazem wiele aspektĂłw przygotowywanego katastroficznego scenariusza zostaĆo w znacznym stopniu podwaĆŒonych przez spoĆecznoĆÄ naukowcĂłw. W tej pracy dokonujÄ krĂłtkiego przeglÄ
du zagadnieĆ naukowych zwiÄ
zanych z globalnymi zmianami klimatycznymi, w tym braku zgodnoĆci danych uzyskanych z obliczeĆ modelowych z danymi uzyskanymi na drodze pomiarĂłw satelitarnych
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Session G: Nuclear Power/Climate Change â Climate v. Climate Alarm
The underlying physics of climate contains important elements that are widely agreed on though frequently misunderstood. In this lecture, the basic physics of greenhouse warming are simply described. It will be shown that the dynamic mixing of the troposphere is essential to the mechanism. It will further be shown that there is nothing intrinsically alarming in the basic physics. Alarm depends critically on the assertion that the climate system is dominated by large positive feedbacks that greatly amplify such warming as may be due to increasing CO2 alone. The nature of possible feedbacks will be described, and the conditions for observationally determining such feedbacks will be explained. It will be seen that the feedback factors, themselves, can be subject to fluctuations, so that large positive feedbacks could occasionally lead to instability. A variety of attempts to evaluate such feedbacks will be described. Some will be shown to be clearly incorrect. The remaining approaches suggest that feedbacks are small and even negative, suggesting little basis for alarm
Comment on "Clouds and the Faint Young Sun Paradox" by Goldblatt and Zahnle (2011)
Goldblatt and Zahnle (2011) raise a number of issues related to the possibility that cirrus clouds can provide a solution to the faint young sun paradox. Here, we argue that: (1) climates having a lower than present mean surface temperature cannot be discarded as solutions to the faint young sun paradox, (2) the detrainment from deep convective clouds in the tropics is a well-established physical mechanism for the formation of high clouds that have a positive radiative forcing (even if the possible role of these clouds as a negative climate feedback remains controversial) and (3) even if some cloud properties are not mutually consistent with observations in radiative transfer parameterizations, the most relevant consistency (for the purpose of hypothesis testing) is with observations of the cloud radiative forcing. Therefore, we maintain that cirrus clouds, as observed in the current climate and covering a large region of the tropics, can provide a solution to the faint young sun paradox, or at least ease the amount of CO<sub>2</sub> or other greenhouse substances needed to provide temperatures above freezing during the Archean
Effects of Planetary Wave-breaking on the Seasonal Variation of Total Column Ozone
The effects of planetary wave breaking on the seasonal variation of total column ozone are investigated using a zonally averaged chemical-radiative-transport model of the atmosphere. The planetary wave breaking effects of zonal wavenumbers k=1 and k=2 are significant in the middle latitude stratosphere during Northern Hemisphere (NH) winter, whereas only wave k=1 is important during Southern Hemisphere (SH) winter. The mixing and induced meridional circulation due to the planetary wave breaking increases the seasonal variation of total column ozone in NH (SH) middle latitudes by âŒ20% (âŒ10%)
Reply to: 'Tropical cirrus and water vapor: an effective Earth infrared iris feedback?'
In assessing the iris effect suggested by Lindzen et al. (2001), Fu et al. (2002) found that the response of high-level clouds to the sea surface temperature had an effect of reducing the climate sensitivity to external radiative forcing, but the effect was not as strong as LCH found. The approach of FBH to specifying longwave emission and cloud albedos appears to be inappropriate, and the derived cloud optical properties may not have real physical meaning. The cloud albedo calculated by FBH is too large for cirrus clouds and too small for boundary layer clouds, which underestimates the iris effect
Significance Tests for Periodogram Peaks
We discuss methods currently in use for determining the significance of peaks
in the periodograms of time series. We discuss some general methods for
constructing significance tests, false alarm probability functions, and the
role played in these by independent random variables and by empirical and
theoretical cumulative distribution functions. We also discuss the concept of
"independent frequencies" in periodogram analysis. We propose a practical
method for estimating the significance of periodogram peaks, applicable to all
time series irrespective of the spacing of the data. This method, based on
Monte Carlo simulations, produces significance tests that are tailor-made for
any given astronomical time series.Comment: 22 pages, 11 Encapsulated Postscript figures, AAS LaTeX v5.2
Submitted to Ap
A Multidisciplinary, Science-Based Approach to the Economics of Climate Change
Economic analyses of environmental mitigation and other interdisciplinary public policy issues can be much more useful if they critically examine what other disciplines have to say, insist on using the most relevant observational data and the scientific method, and examine lower cost alternatives to the change proposed. These general principles are illustrated by applying them to the case of climate change mitigation, one of the most interdisciplinary of public policy issues. The analysis shows how use of these principles leads to quite different conclusions than those of most previous such economic analyses, as follows:
The economic benefits of reducing CO2 emissions may be about two orders of magnitude less than those estimated by most economists because the climate sensitivity factor (CSF) is much lower than assumed by the United Nations because feedback is negative rather than positive and the effects of CO2 emissions reductions on atmospheric CO2 appear to be short rather than long lasting.The costs of CO2 emissions reductions are very much higher than usually estimated because of technological and implementation problems recently identified.Geoengineering such as solar radiation management is a controversial alternative to CO2 emissions reductions that offers opportunities to greatly decrease these large costs, change global temperatures with far greater assurance of success, and eliminate the possibility of low probability, high consequence risks of rising temperatures, but has been largely ignored by economists.CO2 emissions reductions are economically unattractive since the very modest benefits remaining after the corrections for the above effects are quite unlikely to economically justify the much higher costs unless much lower cost geoengineering is used.The risk of catastrophic anthropogenic global warming appears to be so low that it is not currently worth doing anything to try to control it, including geoengineering
Amplitudes of low frequency modes in rotating B type stars
Using weakly non-linear theory of oscillation, we estimate the amplitudes of
low frequency modes in a slowly pulsating B (SPB) star, taking account of the
effects of rotation on the modes. Applying the formulation by Schenk et al
(2002), we compute non-linear coupling coefficient between the low frequency
modes and estimate the equilibrium amplitudes of the modes excited in the star,
assuming the amplitudes of the unstable modes are saturated as a result of
non-linear coupling with stable modes, that is, as a result of parametric
instability expected between one unstable mode and two stable modes. We use the
traditional approximation to calculate adiabatic and non-adiabatic oscillations
in a rotating star. We find -modes in a rapidly rotating star play a
significant role in the amplitude determination through non-linear coupling. We
also find that for low modes, the fractional amplitudes of the radiative
luminosity caused by the low frequency modes are of order to
at the surface.Comment: 14 pages, 6 figures, submitted to Monthly Notices of the Royal
Astronomical Societ
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