Archives par mot-clé : Model(s)

CLIMATE CHANGE WILL TAKE LONGER, SAY SCIENTISTS

by Dr David Whitehouse, September 19, 2017 in GWPF


The study is published in the journal Nature Geoscience by a team of scientists led by Richard Millar of the University of Oxford. It has recalculated the carbon budget for limiting the Earth’s warming to 1.5 degrees Celsius above temperatures seen in the late 19th century. It had been widely assumed that this stringent target would prove unachievable, but the new study would appear to give us much more time to act if we want to stay below it.

See also here and  here

Statistical link between external climate forcings and modes of ocean variability

by Abdul Malik et al., July 31, 2017, Climate Dynamics, Springer


In this study we investigate statistical link between external climate forcings and modes of ocean variability on inter-annual (3-year) to centennial (100-year) timescales using de-trended semi-partial-cross-correlation analysis technique. To investigate this link we employ observations (AD 1854–1999), climate proxies (AD 1600–1999), and coupled Atmosphere-Ocean-Chemistry Climate Model simulations with SOCOL-MPIOM (AD 1600–1999). We find robust statistical evidence that Atlantic multi-decadal oscillation (AMO) has intrinsic positive correlation with solar activity in all datasets employed. The strength of the relationship between AMO and solar activity is modulated by volcanic eruptions and complex interaction among modes of ocean variability.

Paleoclimate Cycles are Key Analogs for Present Day (Holocene) Warm Period

by Renee Hannon, August 4, 2017 in WUWT


Detailed pattern correlation of Earth’s temperature changes during the past 450 kyrs reveals observations about several cyclic climate patterns. The past four glacial cycles are increasing in duration from 89 kyrs to 119 kyrs. Within these glacial cycles, two warm periods occur about 200 kyrs apart and have strikingly similar temperature characteristics.

During the last 450 kyrs, the five major warm onsets with rapidly increasing temperatures are triggered by increases in the eccentricity, obliquity, and precession of Earth’s orbit. The nearly concurrent increase in these three astronomical forces appears a necessary component for a major warm onset. Obliquity is the dominate control for ending these major warm periods and entering a cooling phase. 

Harmonic Analysis of Worldwide Temperature Proxies for 2000 Years

by H.J. Lüdecke and C.A. Weiss, August 2017


We provide a new confirmation for the link between solar activity and climate cycles by wavelet analysis showing a remarkably good agreement of the power of the ~190 – year period for temperatures and solar activity over 9000 years (see Fig.4. lower panel). As (Fig.2 and Table 2 ) show, the periods of ~1000 and ~460 years are also apparently common in records of temperatures and cosmogenic nuclides.

See also here and  here

The IPCC gives us good news about climate change, but we don’t listen

by Larry Kummer, July 29, 2017, in WUWT

Now that the alarmists have had their day trumpeting the IPCC’s worst case scenario (it’s unlikely and becoming more so), let’s look at their best case scenario (hidden by journalists). The risk probabilities are asymmetric: the good news is more likely than the bad news. This is inspirational, telling people that we can make a better world.

Primary energy use per year (in EJ), by source


Scientists Find At Least 75% Of The Earth Has Not Warmed In Recent Decades

by Kenneth Richard, July 20, 2017 in ClimateChangeDispatch


As a new scientific paper (Turney et al., 2017) indicates, the Southern Ocean encompasses 14% of the Earth’s surface. And according to regional temperature measurements that have apparently not been subjected to warming “corrections” by data adjusters, the Southern Ocean has been cooling in recent decades.

CO2 Contributed Only 0.12°C To Global Temps Since 1850

by Kenneth Richard, July 17, 2017


A Swiss scientist known to have published hundreds of scientific papers in physics journals has authored a new scholarly paper that casts serious doubts on the effectiveness of CO2 as a greenhouse gas influencing Earth’s temperatures.

This paper has been added to a growing volume of peer-reviewed scientific papers that seriously question estimates of a high climate sensitivity to significant increases in CO2 concentrations.

On the Validity of NOAA, NASA and Hadley CRU Global Average Surface Temperature Data

by Dr. J. Wallace III et al., June 2017


Abridged research Report, 30 pages, .pdf

The conclusive findings of this research are that the three GAST data sets are not a valid representation of reality. In fact, the magnitude of their historical data adjustments, that removed their cyclical temperature patterns, are totally inconsistent with published and credible U.S. and other temperature data. Thus, it is impossible to conclude from the three published GAST data sets that recent years have been the warmest ever –despite current claims of record setting warming.

See also here

Satellite battle: Five reasons UAH is different (better) to the RSS global temperature estimates

by JoNova, July 10, 2017


There are two main groups that use essentially the same NASA and NOAA satellites to estimate global temperatures. In the last year, they’ve both made adjustments, one down, and one up, getting further apart in their estimates. In ClimateWorld this is a big deal. Believers are excited that now a satellite set agrees a bit better with the maligned “hot” surface thermometers. But UAH still agrees more with millions of weather balloons. The debate continues. Here’s my short synopsis of the  Roy Spencer (and John Christy) from the “Comments on the new RSS lower tropospheric temperature set.” (If something is wrong here, blame me).

Alarm about alarmism

by Judith Curry, July 15, 2017 in ClimateEtc.


In understanding climate change risk, and deciding on the ‘if’ and ‘what’ of ‘action’,  we need to acknowledge that we don’t know how the climate of the 21st century will play out (Deep Uncertainty, folks).  Four possibilities:

  1. It is possible that human-caused climate change will be swamped by much larger natural climate variability.

  2. It is possible/plausible  that the sensitivity of the climate is on the low end of the IPCC envelope (1.0-1.5C), with a slow creep of warming superimposed on much larger natural variability.

  3. It is possible/plausible that the IPCC projections are actually correct (right for the wrong reasons; too much wrong with the climate models for much credibility, IMO).

  4. It is possible that AGW and natural variability could conspire to cause catastrophic outcomes

Focusing on worst case climate futures doesn’t work. It shouldn’t work

by Larry Kummer, July 15, 2017 in WUWT


After 30 years of failure to gain support of the US public for massive public policy measures to fight climate change, climate activists now double down on the tactics that have failed them for so long. This post explains why it will not work. Nor should it. Instead they should trust the IPCC and science, showing both the good and bad news.

Temperature and Forcing

by Willis Eschenbach, July 13, 2017 in WUWT


Over at Dr. Curry’s excellent website, she’s discussing the Red and Blue Team approach. If I ran the zoo and could re-examine the climate question, I’d want to look at what I see as the central misunderstanding in the current theory of climate.

This is the mistaken idea that changes in global temperature are a linear function of changes in the top-of-atmosphere (TOA) radiation balance (usually called “forcing”).

Does a new paper really reconcile instrumental and model-based climate sensitivity estimates

by Nic Lewis, July 8, 2017 in Climate Audit


A new paper in Science Advances by Cristian Proistosescu and Peter Huybers “Slow climate mode reconciles historical and model-based estimates of climate sensitivity” (hereafter PH17) claims that accounting for the decline in feedback strength over time that occurs in most CMIP5 coupled global climate models (GCMs), brings observationally-based climate sensitivity estimates from historical records into line with model-derived estimates. It is not the first paper to attempt to do so, but it makes a rather bold claim and, partly because Science Advances seeks press coverage for its articles, has been attracting considerable attention.

Pronounced differences between observed and CMIP5-simulated multidecadal climate variability in the twentieth century

by Sergey Kravtsov, June 15, 2017


The observed internal variability so estimated exhibits a pronounced multidecadal mode with a distinctive spatiotemporal signature, which is altogether absent in model simulations. This single mode explains a major fraction of model-data differences over the entire climate index network considered; it may reflect either biases in the models’ forced response or models’ lack of requisite internal dynamics, or a combination of both.