As can be seen from Figure 1, all of these global
temperature estimates give pretty much the same result.
So
the temperature estimates they give us are very rough.
Judith, Could you help point to an article or abstract on accuracy of current global
temperature estimates given uncertainties in Arctic, Anarctic, Africa, Asia, South Atlantic ocean and pacific ocean?
Not exact matches
By inputting various data (from vitamin intake to
temperature levels), Glow
gives women «an
estimate of their fertility window via a calendar and an indication of the «percent chance» of getting pregnant.»
Böhm's theory was correct: He
estimated that early thermometers across the Alps
gave summer readings that were 0.7 F above the actual air
temperature.
While a GCM portrayal of
temperature would not be accurate to a
given day, these models
give fairly good
estimates for long - term average
temperatures, such as 30 - year periods, which closely match observed data.
Its method assumes that
estimating the carbon drawdown
gives a reasonable
estimate of the overall effect on
temperatures, and treats low and high - latitude forests equally.
The nuclear spin
temperature is believed to be preserved indefinitely after the formation of a molecule, and hence
gives an
estimate of the
temperature prevailing at the time of the last condensation of the ice.
Given that it doesn't matter much which forcing is changing, sensitivity can be assessed from any particular period in the past where the changes in forcing are known and the corresponding equilibrium
temperature change can be
estimated.
Indeed, the main quandary faced by climate scientists is how to
estimate climate sensitivity from the Little Ice Age or Medieval Warm Period, at all,
given the relative small forcings over the past 1000 years, and the substantial uncertainties in both the forcings and the
temperature changes.
But it turns out that other definitions such as the «adjusted forcing» actually
give a better
estimate of the eventual
temperature change.
The summary
gives various
estimated temperature increases for the 21st century.
If we abandon the models and simply extrapolate the trend, shouldn't that by now, unless there is a huge or unknown
temperature lag,
give us a target with a similar range, and that range would more or less equal the
estimated natural variation?
It may be of spectral and luminosity type MV
given an
estimated mass of 40 percent Solar and a surface
temperature of 3,500 ° K (which is reddish in color).
For instance, models with different parameterization strategies
give very different
estimates of the amount of carbon dioxide in the atmosphere necessary to raise Earth's surface
temperature by 2 °C — with critical implications for policy decisions.
Given that it doesn't matter much which forcing is changing, sensitivity can be assessed from any particular period in the past where the changes in forcing are known and the corresponding equilibrium
temperature change can be
estimated.
The lags are only
estimates, you wouldn't expect all the data sets necessarily to
give the same result, and the difference between surface and lower - troposphere
temperature lags is almost certainly physically meaningful.
Linear regression on monthly
temperature data, for instance, will
give you a reliable trend, but the
estimated * uncertainty * that most computer programs compute for the regression fit will be way off.
Furthermore, the value of 2.8 °C you mentioned is the best
estimate from an analysis of many different models, the likely
temperature rise for the A1B scenario is
given as 1.7 - 4.4 °C by the IPCC, so our result is higher than the best
estimate, but well within the range of all IPCC models.
Regarding Judith Curry, there is broad general agreement that the results released today
give a new and improved
estimate of the global land
temperature going back 250 years.
Any station that is not very rural will suffer from a heat island effect, which may be constant over time but means the station does not
give an unbiased
estimate of the mean
temperature for the area it is supposed to represent.
That then
gives a better
estimate of the actual real world
estimated probability of
temperatures going over 11 degrees F.
In all cases so far, the
estimated rise in
temperature (
given the current level of carbon dioxide) is in the neighborhood of two to three degrees, suggesting that the results are robust.
Given those assumptions, looking at the forcing over a long - enough multi-decadal period and seeing the
temperature response
gives an
estimate of the transient climate response (TCR) and, additionally if an
estimate of the ocean heat content change is incorporated (which is a measure of the unrealised radiative imbalance), the ECS can be
estimated too.
As a final step, after all station records within 1200 km of a
given grid point have been averaged, we subtract the 1951 - 1980 mean
temperature for the grid point to obtain the
estimated temperature anomaly time series of that grid point.
Thus,
given the height and value of the emission
temperature, we can get a simple
estimate for the surface
temperature: 255K + 5.5 km * 6K / km = 288K (= 15oC; close to the global mean
estimated from observations
given by NCDC of ~ 14oC).
Their approach requires an
estimate of the forced global mean
temperature in a
given year (excluding any natural variability), which are derived from Otto et al (2015), who employ a regression approach to reconstruct a prediction of global mean
temperatures as a function of anthropogenic and natural forcing agents.
Indeed, the main quandary faced by climate scientists is how to
estimate climate sensitivity from the Little Ice Age or Medieval Warm Period, at all,
given the relative small forcings over the past 1000 years, and the substantial uncertainties in both the forcings and the
temperature changes.
The unforced
temperature estimate is used as a proxy for what cumulative emissions should be
given the current level of warming.
Comparing the yearly and
estimated temperature,
gives us a long term
temperature trend upward of about 0.3 deg.
You stated: «Thus,
given the height and value of the emission
temperature, we can get a simple
estimate for the surface
temperature: 255K + 5.5 km * 6K / km = 288K (= 15oC; close to the global mean
estimated from observations
given by NCDC of ~ 14oC).»
A lot of the observation based
estimates are likely biased low, as outlined in the Ringberg report just due to assumptions of linearity in the evolution of surface
temperature in response to some
given radiative nudge on the system.
Observational errors on any one annual mean
temperature anomaly
estimate are around 0.1 deg C, and the errors from the linear fits are
given in the text.
So the two
estimates (with and without solar forcing)
give me a range of 0.7 C to 1.4 C for the 2xCO2 climate sensitivity, based on actually observed CO2 and
temperature records, rather than model simulations and assumptions.
I think this has merit even as a cross check BUT, any system where
temperatures are
estimated from surrounding sites are affected by the time lags — For example there is no relationship between Adelaide and Melbourne on any
given day but there IS a relationship between Melbourne and Adelaide lagged by one day because the predominant west to east motion of weather systems in this part of the world.
Yes, the data set for the polar regions is far more sparse and subject to educated extrapolations that other regions, but excluding any
estimate at all for
temperature changes in these all important polar regions by excluding them is to to
give an incomplete and, IMO, quite inaccurate, view of climate change.
One of the early objectives of the new system would be to refine the model so that it better matched the measured
temperatures, thus
giving better
estimated temperatures.
It wouldn't even matter if at a
given location on a particular day the
estimated maximum
temperature was lower than the
estimated minimum
temperature.
For this reason, a number of researchers have suggested that it should be possible to
estimate the long term Sea Surface
Temperature trends for a
given area by averaging together all the available measurements from different voyages that went through that area in a
given month.
To
estimate uncertainty in total committed rise
given some
temperature increase, we use the derived Antarctic intervals, plus the ranges for the first three SLR components as shown in figure 2 A — C of ref.
For instance, models with different parameterization strategies
give very different
estimates of the amount of carbon dioxide in the atmosphere necessary to raise Earth's surface
temperature by 2 °C — with critical implications for policy decisions.
Thus 3,000 ARGO buoys do not
give 3,000 independent
estimates of the ocean heat content at a particular time; each observation
gives a single
estimate of the
temperature at a particular location and depth.
Given BP, SL, and sea surface
temperature fields, good
estimates of full - column HC variations can be made at low and middle latitudes.
The consistency between these two data sets
gives confidence in the ocean
temperature data set used for
estimating depth - integrated heat content, and supports the trends in SST reported in Chapter 3.
Satellites supposedly overcome that concern about UHI by sampling uniformly in order to
give a true
estimate of global mean surface
temperature.
Fortunately, the negative and positive forcings are roughly equal and cancel each other out, and the natural forcings over the past half century have also been approximately zero (Meehl 2004), so the radiative forcing from CO2 alone
gives us a good
estimate as to how much we expect to see the Earth's surface
temperature change.
If the two methods do lead to different
estimates of climate sensitivity, I find it difficult to believe that the 1D model is more appropriate than 3D to making claims about how much the real average
temperature will rise due to a
given influence.
Paleo recontruction of
temperature and CO2 levels
give another
estimate.
It is therefore erroneous to suggest that the
estimate of the global average ocean
temperature is
given by the instrument accuracy divided by the square root of the number of observations (as you would if the observations were of the same quantity):
«[it is] erroneous to suggest that the
estimate of the global average ocean
temperature is
given by the instrument accuracy divided by the square root of the number of observations (as you would if the observations were of the same quantity).»