Predicting Climate

Models

Models are a way to describe or represent the world. They assist with making predictions about the future, for example weather predictions are a result of making observations and projecting future weather conditions over the next week using mathematical formula.

Models are also used to predict future changes to the amount of greenhouse gas that will be released into the atmosphere and the effect of greenhouse gas emissions (climate change). Scientists use different types of models for different purposes. Here is a list of 5 different types of climate models:

• Energy Balanced Models are useful to gain an understanding of how energy flows behave overall, how changes in greenhouse gas or reflectivity influence Earth’s temperature.
• Earth System Models represent climate in more detail. They provide representations of climate patterns over oceans and continents for long periods into the future. This type of model requires relatively few calculations.
• General Circulation Models are more detailed and describe more processes. They are used to describe patterns in the atmosphere and oceans. This type of model requires more equations and thus takes more computational time.
• Regional Climate Models are finer scale models linking what is going on globally to what is happening in a region. They are better at explaining regional events, floods, hurricanes and heat waves.
• Integrated Assessment Models aim to provide predictions of climate impact that are complex. They are used to calculate the benefits of investing money, and effort into climate change adaptation.

Scientists are continually adding more sophisticated calculations to climate models. Aspects of climate systems are yet to be understood and incorporated into the models.

Back-casting (the opposite to forecasting)

Instead of predicting what will happen in the future, it may be better to work backward from what we want and determine what is required to achieve our targets. What must we do to achieve results?

Risk Perception

How does experience of events affect one’s expectations about the future? What is the impact our perception of risks on our emotions? Risk perception involves awareness of the hazards, and the likelihood that risks will affect one’s life.

Calculating risks involves both describing and predicting the future.

Predictions

Earth’s future is uncertain, current projections are for global warming of between 2.4 and 6.4 degrees; increasing intensity of precipitation events, floods and droughts and rapid melting of glaciers that will lead to permanent rise in sea level, with feedback effects that will amplify climate warming.

Predicting climate change is based on an array of social, economic and political factors affecting the release of greenhouse gases such as:

• Energy consumption: How many more people will consume energy? How far and how often will people drive? Will homes and cars become more efficient? Will industrial production increase or drop?
• Food: What kind of food will we eat? How will it be grown?
• How much will population increase?

Uncertainty leads to surprises.

Scenarios

Will precipitation come in occasional great deluges with flash floods and long periods of drought? What will happen as a result of more storms and more drought? Will the result of global warming become more forceful and will storm systems occur more frequently? How will all of this affect river runoff, food production?

How much will sea level rise? Will climate change lead to changes to ocean circulation, with feedback accelerating warming?

What will life be like in the future? What are the possibilities?

A Scenario for 1.5% rise in earth’s temperature

A 1.5% temperature will be far from impact free and will lead to extreme temperatures, precipitation events and an increase in the severity and frequency of droughts in some regions. Coral reefs are expected to decline by a further 70-90%.

Keeping temperature rise to the 1.5% target would require a massive and very rapid transformation of human life.

Facing the Reality of Global Warming

Humans are already committed to at least 2-2.5 degrees of warming regardless of how quickly we reduce emissions of greenhouse gases. Scientists are beginning to explore the possibility that we will reach major thresholds beyond which warming may accelerate uncontrollably. By 2100 the planet may be at 2.4-6.4% warmer.

The challenge is to reduce emissions by 80-90%.