The term "climate change" describes the evolution of the planet's climatic circumstances. Numerous internal and external variables both contribute to this. Over the past few decades, the climatic shift has attracted attention on a global scale. Additionally, these climatic fluctuations have a variety of effects on earthly life. Urbanisation leads to climate change, which is a serious problem that we must address. The ecosystem and ecology are being impacted in different ways by these climate changes. Many plant and animal species have vanished as a result of these changes.
Advance climate assessments and a fundamental understanding of climate change are provided by climate research. As a result, we can better prepare for change and its effects and take the necessary precautions to prevent disasters.
Modelling allows us to recreate these multifaceted phenomena using computers to approximate reality. It also gives us the possibility of experimenting. For instance modifying human-induced greenhouse gas emissions, without actually using the earth as a laboratory. A climate model is a sophisticated piece of computer code that reproduces Earth digitally. The processes and interactions between the atmosphere, ocean, and land surface in the Earth's climate system are modelled in this model. The model's output can be used to calculate the impact of future climatic changes. However, it is challenging to create such models, and they might not be flawless or accurately reflect the real environment. Over time scientists and researchers have improved the representation of processes with higher resolution and complexity bringing realism and relevance to the simulations.
An international initiative that aids in coordinating international climate research is the World Climate Research Programme (WCRP). To better comprehend this climate change, a collaborative framework called Coupled Model Intercomparison Project (CMIP) was developed. It has been developed in phases to foster climate model improvements but also to support national and international assessments of climate change. CMIP uses the outputs of various GCMs to predict the results.
GCM mentioned here is an acronym for General Circulation Model and it is a type of climate model. It makes use of a mathematical model of a planet's atmosphere or ocean's overall circulation. Computer programmes that model the atmosphere or oceans of the Earth are built on the foundation of these equations. Along with sea ice and land-surface components, atmospheric and oceanic GCMs (AGCM and OGCM) are essential elements. Weather and climate forecasting as well as studies aimed at bettering our understanding of the climate system are the two main uses of GCMs.
The objective of the Coupled Model Intercomparison Project (CMIP) is to better understand past, present and future climate changes arising from natural, unforced variability or in response to changes in radiative forcing in a multi-model context. This understanding includes assessments of model performance during the historical period and quantification of the causes of the spread in future projections. An important goal of CMIP is to make the multi-model output publically available in a standardised format. Twenty years ago, CMIP began as a comparison of a few pioneering global coupled climate models. It has later expanded into a sizable effort to promote model development and scientific knowledge of the Earth system in response to a rising need to systematically assess linked ocean and atmosphere model outputs from numerous climate modelling centres. In order to achieve these additional objectives, CMIP has created clearly defined climate model experiment procedures, formats, standards, and distribution mechanisms to make sure that model output is accessible to a large research community.
CMIP has been released in 6 phases till now. The most recent iteration of the CMIP, often known as CMIP6, was made public as phase 6. It contains more plausible climatic forcing scenarios for past, paleoclimate, and future scenarios (various SSPs). By offering a comparable framework called CMIP Diagnostic, the structure of the CMIP6 has been expanded in comparison to the CMIP5. Additionally, CMIP6 seeks to be uniform in its use of common standards and documentation. In order to do that, it comprises techniques that make it easier for model outputs to be distributed widely and characterised, as well as shared standard tools for their analyses. There are numerous manuals available for users, modellers, and data managers.
CMIP6 includes over 100 models from more than 50 modelling centres. By combining many different models and thus forming an ‘ensemble’, we can extract information about the full range of possible future climate changes and the associated uncertainties.
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