The use of computer models runs right through the heart of climate science. From helping scientists unravel cycles of ice ages hundreds of thousands of years ago to making projections for this century or the next, models are an essential tool for understanding the Earth’s climate.
A global climate model typically contains enough computer code to fill 18,000 pages of printed text; it will have taken hundreds of scientists many years to build and improve; and it can require a supercomputer the size of a tennis court to run.
The models themselves come in different forms – from those that just cover one particular region of the world or part of the climate system, to those that simulate the atmosphere, oceans, ice and land for the whole planet.
The output from these models drives forward climate science, helping scientists understand how human activity is affecting the Earth’s climate. These advances have underpinned climate policy decisions on national and international scales for the past five decades.
In many ways, climate modelling is just an extension of weather forecasting, but focusing on changes over decades rather than hours. In fact, the UK’s Met Office Hadley Centre uses the same “Unified Model” as the basis for both tasks.
The vast computing power required for simulating the weather and climate means today’s models are run using massive supercomputers.
The Met Office Hadley Centre’s three new Cray XC40 supercomputers, for example, are together capable of 14,000 trillion calculations a second. The timelapse video below shows the third of these supercomputers being installed in 2017.