In our series of climate models, this is the second write up, please hooked up to our website to explore more in the series.
As for different climate models put into use, we begin with Energy balance Models (EBM) and such are generally termed s primary climate models and the processing is obviously based upon basic numerical equations and the logical synergy between them. In fact, calculation was not essentially reflected in such models, rather, it is about the comparison between sunrays striking earth’s surface and the heat bounced up back into the space.
Now, talking about climate variable that came under calculation was earth’s temperature, while such EBMs ran on a handful of codes, that can be implemented even on a spreadsheet.
Further, such models are designed to treat earth as a single unit or point and are thus “zero dimensional” while others are 1D where energy transmission across diverse latitude on earth, are also taken into consideration, in the form of distance between equator and the poles.
A step further, after EBMs, we have Radiative Connective Models, designed to record energy transmission when it passes through atmosphere, like when there is an increase captured in warmer air. Apparently, such models are designed to carry out calculation of temperature and humidity across several atmospheric levels logically considered for such a purpose.
Such models are basically 1D, i.e. only the energy that shorts upwards, is taken into account but in recent years, efforts are put to design 2D models as well.
Following this, we have General Calculation Models (GCMs) which are also referred to as Global Climate Models wherein climate physics and such dynamics is gathered and is processed and synergy. For instance, air and water flows, including oceans and the reflection of heat in the atmosphere.
Truth be told, initial GCMs, although considered one aspect on earth and such could be either ocean or atmosphere models but such a supreme simulation was done in 3 dimensional way wherein hundreds of kilometres of elevation in the atmosphere on several kilometres deep in oceans also got notable representation during critical analysis.
Not surprisingly, there were also developed models, which were coupled and thus, were more sophisticated to ingest distinct aspects together and several models were connected and climate system was given a full-fledged representation thereby. For instance, we have AOGCMs (Atmosphere Ocean General Circulation Models, designed to mirror the transfer of heat and freshwater taking place between land and ocean as well as into the air too.
The following infographic explains the way model each aspect or member of climate framework are bound in a typical global coupled models during the past decades.
It is commendable job on part of climate scientists that different aspects of earth system have been included into the GCMs, else such would have considered only a single aspect, either land, sea ice, land ice etc.
As a versatile aspect of new age GCMs, the erstwhile biogeochemical cycles are also given way in, i.e. chemical trade off between living things with the environment they inhabit and their action and reaction within the climate system at length. Revealing details, such “Earth System Models” now reflect the entities, namely carbon cycle, nitrogen cycle chemicals present in the atmosphere, ecology of oceans, vegetation aspect and the basic change therein, use of land surface and so forth, solely because such factors are the deciding factors in climatic response to green house gas emissions caused by human activities.
Precisely, there is vegetation responsive to temperature and rainfall which responds to release of greenhouse gases and of carbon into the atmosphere. At the University of Aberdeen, Prof Pete Smith, who lectures about soil and global change did not fail to term ESMs as “pimped” forms of GCMs and went on to state,
“The GCMs were the models that were used maybe in 1980s. So these were largely put together by the atmospheric physicists, so it’s all to do with energy and mass and water conservation, and it’s all the physics of moving those around. But they had a relatively limited representation of how the atmosphere then interacts with the ocean and the land surface. Whereas an ESM tries to incorporate those land interactions and those ocean interactions, so you could regard an ESM as a “pimped” version of a GCM”.
Apart from these, there have also been developed Regional Climate Models (RCMs) tasked with similar kind of objectives to meet, as GCMs do, but such are designed to cover limited area and therefore, their performance and output is quicker than most of the other systems, as only a limited piece of land is to be focussed upon and resolution is high too in comparison to GSMs. Being a high resolution system means there are smaller grid cells and hence climate data is captured, processed and output in greater detail but for a limited piece of land.
In final lap of our discussion, I would like to cover Integrated Assessment Models (IAMs), where social response which shape up simple climate model in its unique ways, such as growing population, industrialization and fuel use and how such implicate physical climate.
Further, such systems reflect scenarios indicating variety of greenhouse emissions in years to come and climate scientists can utilize such aspects through the prism of ESMs to gather forecasts about climate change and such data can be valuable in formulating environment policies and energy use rules on our planet.
Then, benefits of implementing such policies and costs associated with them, can also be assessed in regard to undertake the challenges of greenhouse emissions. Like, the carbon’s social costs and assaying the financial costs of such impact and then advantages and disadvantages of additional release of CO2 which gets released and so forth.