Scientific Projections

6.1.1

Scientific predictions or forecasts describe the most likely future. Predictions of the future are based on the most accurate and reliable data from past and present conditions. Predictions assume no change in present contributing conditions Scientific predictions have a degree of certainty.

E.g. What will the concentration of atmospheric CO2 be in 2010?

Scientific Projections are responses to chosen new factors in predictions. Scientific Projections answer the question ‘What if? ‘ for a prediction. Projections assume additional factors or conditions will influence the prediction. Since conditions may evolve differently than predicted, projections have substantial uncertainty.

E.g. If the concentration of atmospheric CO2 emissions tripled in 2010, what would be the global temperature?

Scientific projections vary since they depend on the ‘what if ‘ question being asked. The ‘What if?’ question becomes the driving force or forcing condition used to project a possible future. The forcing chosen is the additional consideration to be used in projecting the future. Climate projections depend on the ‘forcing’ used such as emission, concentration or radiatiive forcings. Climate projections often a used as raw material for climate scenarios. Eg. CO2 emissions.

Climate Scenarios use a reasonable projection of future climate influenced by forcings or changes in conditions due to human activity. Climate scenarios are the ‘What if?’ questions that are often asked of a climate model. Climate scenarios are used when investigating potential consequences of conditions changed due to human activity.

E.g. ‘What will the concentration of atmospheric CO2 emissions due to human activity be in 2010, if sales of hybrid cars increased by 10% ‘?

Climate Change Scenarios represent the difference between the climate scenario and the current climate.
E.g. What if the CO2 emissions triple from the present concentration of 370ppm?

Activity:
1. See also 2.2. and 2.3

2. Find graphs in ‘Climate Change in Context’ which represent each of the terms mentioned:
a. scientific prediction
b. scientific projection
c. forcing
d. climate scenario.

3. Research: Why the concern regarding the concentration of atmospheric CO2? See 5.1.1
a. What has been the % increase in the concentration of CO2 since 1750?

4. The present concentration of CO2 has not been exceeded in the past 420,000 years and is not likely to have been exceeded in the past 20 million years. The current rate of increase has never occurred in the last 20,000 years.
a. What was the CO2 concentration in the year 1000?
b. What percent increase occurred to the 2000 ?
c. What is the best socio-economic scenario for CO2 ie least increase of CO2? A1B, A1T, A1F1, A2, B1, B2 ?