We’re rewarding the question askers & reputations are being recalculated! Read more.
38

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 ...


23

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

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 ...


16

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. ...


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 ...


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&...


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

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 ...


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 ...


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 ...


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

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

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 ...


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 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 ...


7

$M$ 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 ...


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 ...


7

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 ...


7

We are moving all of CESM to open source - in particular here is the latest version of the Community Terrestrial Systems Model (CTSM) https://github.com/ESCOMP/ctsm Formerly known as CLM, CTSM includes capability to run on linux or MacOS systems.


7

Definitely not. A Heinrich event requires massive ice sheets to grow and then collapse in the Northern hemisphere. The large outflow of icebergs that would result form such collapse would deliver fresh water and debris to the North Atlantic, which is what constitutes a Heinrich event. These events are detected by existence of deposits of ice rafted debris ...


7

There is no doubt that the sooner the mitigation effort happens, the greater will be its impact. In other words, the impact on year 2100 climate of the sequestration of 20 billion tons $\ce{CO2}$-eq right now, is much bigger than the impact that the same action will have in 30 years from now. Therefore, a mitigation action today is much cheaper than one ...


6

I think it is important to think of the El Niño as just one of the components of a large scale global atmospheric-oceanic phenomenon known as the El Niño and the Southern Oscillation (ENSO). ENSO takes shape as fluctuations of the rainfall, wind, ocean currents and waves. They are by nature very irregular. The Southern Oscillation (SO) was first discovered ...


6

The answer to this question depends on what process one is interested in simulating well. As you know, short/mid-range weather prediction models and climate models have very different applications and goals. Because the short range weather prediction model is typically of much higher resolution than climate models (~1-10 km versus ~50-200 km), it is almost ...


6

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 ...


6

There are several climate datasets around the world, two in America - NASA's GISTEMP, and NOAA's MLOST, and one in the UK - HadCRUT. These are the main datasets but there are others around the world, China, Japan etc. The datasets differ slightly in the starting date, number of met stations included, degree of interpolation, and the way they get round the ...


Only top voted, non community-wiki answers of a minimum length are eligible