Because we can't know the future for certain, our climate change scientists use computer-based climate models to project plausible scenarios, or projections, for coming centuries.
It is important to be aware that projections from climate models are always subject to uncertainty because of limitations on our knowledge of how the climate system works and on the computing resources available. Different climate models can give different projections.
The projections are also based on emissions scenarios, such as the level of CO2 emissions increasing or decreasing. Many different scenarios are used, based on estimates of economic and social growth, and this is one of the major sources of uncertainty in climate prediction. But even if greenhouse gas emissions are substantially reduced, the long lifespan of CO2 in the atmosphere means that we cannot avoid further climate change due to CO2 already in the atmosphere.
Despite the uncertainties, all models show that the Earth will warm in the next century, with a consistent geographical pattern.
The globes below show latest results from the Met Office's climate change research. The data are based on a mid-range IPCC emissions scenario A1B
Watch the temperature changes in HD on the Met Office YouTube channel
Watch the animation in HD on the Met Office YouTube channel
The computer climate models used for the majority of the work at the Met Office Hadley Centre are detailed three-dimensional representations of major components of the climate system. They are mostly run on the Met Office's supercomputers. As part of the Met Office's Unified Model, the atmosphere component of the climate model represents the same physical processes as that used for operational weather forecasts. However, due to the longer timescales involved in climate prediction, other components of the climate system are added including:
three-dimensional representation of the ocean and sea ice;
an interactive carbon cycle model;
interactive atmospheric chemistry models;
the coupled atmosphere - ocean - carbon-cycle - chemistry model is known as an earth system model.
For both weather and climate prediction, the Met Office also runs its models at higher resolution over particular regions. Currently regional climate models are typically run at 25 km resolution.