What are climate models?
Climate models are computer programs that simulate the behaviour of the Earth's climate system. They work by representing the Earth as a set of grid boxes or cells, with each cell containing information about temperature, pressure, humidity and other relevant variables. The models use mathematical equations to simulate how these variables interact with each other over time.
How do climate models and weather forecasting differ?
1. Time scale
Climate models are designed to simulate long-term changes in the Earth's climate (decades or centuries). Weather forecast models are designed to simulate short-term weather patterns (days or weeks).
2. Spatial scale
Climate models typically have a coarser spatial resolution than weather forecast models, as they are focused on capturing large-scale processes (such as global ocean currents). Weather forecast models need to capture small-scale features (such as individual storms and weather fronts).
3. Input data
Climate models are designed to explicitly incorporate the interactions between the atmosphere and other components of the Earth’s system (particularly the oceans). Weather forecast models are primarily forced by atmospheric parameters and so rely primarily on observational data such as temperature, humidity and wind.
What are the Shared Socioeconomic Pathways (SSPs)?
Shared Socioeconomic Pathways (or SSPs) are scenarios used in climate modelling that describe different possible trajectories of global socioeconomic development over the next few decades. They were developed to provide a common framework for exploring the relationship between different climate change mitigation and adaptation policies and socioeconomic development.
- SSP1 (also called Sustainability) represents a future with strong emphasis on sustainable development, low population growth, and low fossil fuel use, with an increasing use of renewable energy and improved environmental policies.
- SSP2 (known as Middle of the Road) represents a future with moderate population growth, intermediate economic development, and fossil fuel use continuing as today, with some improvements in efficiency and environmental policies.
- SSP3 (also known as Regional Rivalry) represents a future with slow population growth, slow economic development, and a continuation of existing regional rivalries, with limited international co-operation and investment in clean energy.
- SSP4 (or Inequality) represents a future with high levels of inequality, low population growth, and fossil fuel use continuing at current levels, with limited investment in clean energy.
- SSP5 (also called Fossil-Fuelled Development) represents a future with rapid population growth, high levels of economic development, and continued high use of fossil fuels, with limited investment in clean energy and weak environmental policies.