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I want to know if that article has been refuted anywhere
Yes. You can read all about it in the blog post
James Taylor misinterprets study by 180 degrees.
In short, the original paper was designed to test the view of "professional geologists", which in this case are members of the Association of Professional Engineers and Geoscientists of Alberta. The vast ...
24
The butterfly is a colourful illustration of Chaos Theory, and the word butterfly came from the diagram of the state space (see below).
A system that is chaotic is extremely sensitive on its initial value. In principle, if you know exactly how the state of the universe is now, you could calculate how it develops (but due to other reasons, it is ...
17
You might take a look at the Technical Summary of the most recent IPCC Assessment Report (5).
Thematic Focus Element #3 is "Comparing Projections from Previous IPCC Assessments with Observations"
It says:
Global Mean Temperature Anomaly
Relative to the 1961–1990 mean, the GMST anomaly has been positive and
larger than 0.25°C since 2001. ...
17
Ivar's graph is mischievous in trying to imply that there should be an exact correlation. The global air temperature is not a good parameter to chart against CO2 emissions because the increasing heat doesn't just warm up the air. Most of the heat goes into warming the upper layers of the oceans, but it is not a linear relationship. The ratio of air and ocean ...
16
I gave a longer answer linked to a similar question in the comments above, I'll give a quick one here:
There's a story going around the low-grade news factories that one Dr.
David Evans . . .
Everyone knows there's a fair bit of "I know you are but what am I" in the climate change debate (if you can even call it a debate), but whichever side you agree ...
13
Predictability: Does the flap of a butterfly's wings in Brazil set off a tornado in Texas?
That was the title of Edward Lorenz's invited talk at the 139th meeting of the American Association of the Advancement of Science held in 1972. This is the origin of the term "butterfly effect". The catchy title suggests that the answer must be "Yes!" Why else ask ...
13
Your question is fairly broad, and slightly vague so I don't know if I will be able to answer it in one go. If you would like any clarification, let me know.
How are predictions made?
The basic process generally used for probabilistic forecasting of the global climate is something like:
Take one or more general circulation models (GCMs), and run multiple ...
12
Full scale climate models
The atmospheric climate simulations that are presented in the IPCC reports are performed by quite large and complex models. Running these models needs a "supercomputer" (high performance cluster). Additionally, certain "forcing data" and "boundary conditions" are needed.
Boundary conditions are the top ...
11
All season forecast systems are subject to uncertainty. The uncertainty arises from an imperfect initial state, such as initial conditions, and from imperfect models, such as uncertainty due to, numerical methods, parametric models, data sampling. Forecasting systems utilize ensembles and their spread to quantify uncertainty.
See the spread in forecasts ...
11
A model is a simplified representation of a system.
Rather than try to model everything down to the microscopic level, or as vectors, we often aggregate phenomena across geographic areas, to simplify the computation a lot, and to lose only a little accuracy and precision.
So if I want to model the UK, which roughly spans 8°W - 2°E, 50°N - 60°N, that's an ...
11
First things first: There's nothing per se wrong in science with answering "We don't know" to a vexing problem. This might well be one of those cases.
The question you are asking was asked by Imbrie and Imbrie in 1980. The problem you have noticed (a very strong interglacial despite low Milankovitch forcing) is now known as the "stage 11 problem", and this ...
10
Yes, there were many model coupling projects in the past, as well as many ongoing coupling projects in the present and near future.
The main motivation behind model coupling is the need for the interactive feedback processes between two or more separate physical systems, for example, atmosphere and ocean. Historically, these models have been developed ...
10
Coupler software (e.g. OASIS, MCT, C-Coupler) is frequently used to combine these different components of earth system models. Of course interfacing models with each other using these couplers or other methods always needs some technical work and sometimes also some algorithmic work. Therefore the number of model combinations will always be limited.
10
Omega, ω is closely related to w in meteorology.
It can be moved towards w using the chain (this reminder from Watkins at SJSU helped)...
ω = dp/dt = (dp/dz)(dz/dt) = (dp/dz)w
[where p is pressure, t is time, z is height, and w is vertical motion in height coordinates]
Often in general meteorology you can estimate dp/dz using the hydrostatic ...
10
Your question is simple enough, but the answer depends on what exactly you're looking for.
Who is emitting where right now?
Real-time global monitoring of greenhouse gas emissions with a high spatial resolution is an emerging technology. We have very useful satellites (see Jean-Marie Privals answer), but they have limitations:
All existing public ...
9
Be warned this is a general (and speculative) answer, but it was getting too long to be a comment: The bulk of Greenland's ice mass is centred over inland/central Greenland. If you were to take all the ice away today, much of central Greenland would actually be below sea level, by several hundred metres in fact:
Glacial isostatic rebound would seek to ...
9
climate data operators (CDO)
define grid
We define a lat-lon target grid with 1°x1° grid cell size 30x30 grid cells starting at 40°N and -10°E (=10°W):
gridtype = lonlat
xsize = 30
ysize = 30
xfirst = -10
xinc = 1
yfirst = 40
yinc = 1
This text is written into a text file. See section 1.3.2 CDO Manual for details and ...
9
As alluded to in some of the comments, all of the CMIP5 models will have been run on supercomputers, and it takes a lot of effort to get one of them running on a new platform, even for a team who know both the model and platform well already. In addition to that, many of those models are closed-source and are not generally available to an individual ...
9
I can imagine a satellite observation-based model that calculates
emissions on a spatial basis but I am not sure if our technology is
advanced enough to do that accurately.
It is. The first satellite designed to measure GHG is GOSAT, from the Japanese space agency, launched in 2009 and still active today. It was followed by Nasa's OCO-2 in 2014. GOSAT ...
8
The short answer is that most of the Earth's original allotment of CO2 got locked up in various carbonate minerals, largely calcite (limestone, marble, and chalk). According to this article there is currently ~800 gigatons of carbon in the atmosphere today; there is ~39,000,000 gigatons of carbon locked up in calcite minerals. All that carbon was once in ...
8
Temperature differences y/y are very small compared to natural variation during the year
This is only saying that we have a large seasonal cycle. It says nothing about low-frequency variations. Once you remove seasonal effects, the centennial scale warming is obvious and nearly ubiquitous (yes, a handful of regions have been cooling recently, but the vast ...
8
$M$ is the forward model you are using. It is the dynamical model used to solve whatever discrete equation evolves the field ($d?/dt=$).
The best way to start with data assimilation and understand its nomenclature is to read Ide et al. (1997). In their work, they explain it as:
A discrete model for the evolution of an atmospheric, oceanic, or coupled ...
8
A good start is the article by Goodkin et al. (2008) that relates past fluctuations of NAO to climate variability and argues that in the late 20th century NAO changes are much more dramatic as a result of enhanced energy (temperature) in the northern hemisphere. (Source WHOI)
Visbeck et al. (2001) describe the complex relationship between NAO and climate ...
8
TLDR;
The precipitation values (and possibly some other variables; see below) need to be divided by 24.
Background
The global attributes of the netCDF file in the question provide an URL to a description page: coastmod.hzg.de
From that URL a user should be redirected to wiki.coast.hzg.de/display/MD (access at 9th Feb 2018). Unfortunately, the redirect ...
8
In this regard you can think that the Earth system is like a house with heating but no Air conditioning. Therefore, it has a powerful mechanism to stay warm when the solar illumination is weak (greenhouse effect), but it has no such powerful mechanism to cool down if the solar illumination is too strong.
In hour analogy, let's say you have used your heating ...
8
In general, the relation between the three datasets is as follows:
The simulation model is initiated with a set of boundary and initial conditions, and will on the long-term provide good mean conditions. However, depending on the frequency of data assimilation, the results on short-term time spans can deviate from the observations, due to internal ...
7
Energy balance in the winter is highly dependent on the total amount of area covered by snow or ice. Snow increases the albedo of the Earth which directs the short-wave radiation from the Sun back to space, stopping it from being absorbed by the Earth. Winters with minimal snow/ice cover effectively allow more solar radiation to be absorbed by the Earth. ...
7
Temperature differences y/y are very small compared to natural
variation during the year, and the trend we see could be statistical
illusion, especially that the scientists who developed the method were
looking to demonstrate exactly that sort of trend.
Fortunately statisticians have developed tests to determine whether the evidence for a warming ...
7
There have been a range of studies on the issue published in Atmospheric Chemistry and Physics and other scientific journals.
The short answer is "yes." The longer answer is "yes, but...."
In Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection, Jones, et. al. (2016) note:
In this paper, we examine the ...
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In short, I would say that it is too soon to say. But, if I were forced to guess: I would indeed incline to say that we live in a RCP 8.5-ish scenario.
I'm not an expert at all on climate models or RCP scenarios, but I found the question interesting, so this is my attempt to answer it based on the most reliable data sources I found. I hope to motivate ...
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