OUR MISSION: As our climate changes, ACER supports communities with grassroots initiatives to plant trees, and educates on how to measure, monitor and report on tree health and growth.

Scientific Projections




Some people are confused with all the climate change information that is now available.

Some people – including many scientists – are concerned about the future impacts of climate change.

Some people are anxious because of the enormity of the task of changing our present practices.

But what can the average person do?

  • Become informed.
  • Discuss the information with others.
  • Come to some understanding. Move to change attitudes and behaviours- starting with yourself – towards the environment!
  • Make a difference!!

Some skeptics argue that the human influence on climate change has not been proven, and therefore it is premature to respond.

“Our belief in any particular natural law cannot have a safer basis than our unsuccessful attempts to refute it.” Sir Karl Raimond Popper, philosopher of science.

Source: Popper, J.K.R. 1979. Conjectures and refutations: the growth of scientific knowledge. Routledge, London.

Popper’s argument suggests that many of our scientific laws are accepted on the basis of failure to disprove, rather than on the basis of proof.


This argument is also the basis for research and discussion.

Scientific projections use present trends and impacts of climate change in Ontario to allow us to look ahead and forecast conditions as far ahead as 2100.

Some projected impacts of climate change on Ontario are already here. Check the ice reports from Hudson’s Bay, Lake Huron lake levels, or Lake Simcoe ice free days!

Future impacts of climate change in Ontario has two main parts each with information and activities:

6.2.1 – The science of future climate – greenhouse gases, temperature, precipitation, and weather extremes

6.2.2 – Sectors of our society and the future they face with a changing climate.

Check out the future in Ontario by clicking on the topic of your choice.

6.2.1 Introduction – A look ahead and how to measure what the future may hold.

Reliability of Projections, Uncertainty, Degrees of Confidence, and Reasons for Concern.

The Uncertainty of Climate Change and Impacts.

From www.ijc.org Climate Change and Water Quality in the Great Lakes Region, 2003.

Most of the climate change impacts described are developed from impact assessments.

Impact assessments are based on case studies of sensitivity to current and historical climate (extreme events). These assessments identify risks due to climate change.

Uncertainties about the causes of climate change, the rate and the magnitude of the changes, and the associated impacts to the Great Lakes region lead to ambiguity. Ambiguity limits adaptations and actions to deal with impacts.This creates a challenge for society as a whole to believe

  • that human activities contribute to climate change,
  • that climate change is an issue to be concerned about, and whether they should act.
  • Without a high degree of certainty, public understanding, and support, policy and decision-makers, although concerned, are not necessarily disposed to act.

However, uncertainty should not be used as an excuse not to act.  Failure to adapt may leave the Great Lakes region poorly prepared to cope with negative changes, and with increased probability of severe consequences.

As the climate continues to change, society’s ability to protect sensitive systems may be further challenged.  In addition, like the acid rain issue, there may be climatic surprises, for example, unanticipated effects or a threshold change which may not necessarily be reversible after the stress is reduced or removed. Climate change scenarios are used as models to project future conditions (for example, ecosystems and economic sectors) and thus empower society to better prepare for the future. (See also What We Can Do – Spheres of Empowerment.)

Temperature Change 1900 to 2100 and Reasons for Concern

Source:IPCC Climate Change (2001) Synthesis Report Working Group 1, 11, 111 www.ipcc.ch.

1. Find the continuation of the line plotting the observed data into the next century.
2. How many degrees change in global temperature are shown on this line for 2100?
3. Where does this line lie with respect to all the other model scenarios? What does this mean? Hint: Check the basic concepts for each of the scenarios.
4. How are the 2 graphics related?

ACTIVITY 3 Research
1. Choose one Reason for Concern (1-V) and describe what this chart means and relate it to the temperature graph.
2. What is believed to be the major cause of the temperature change shown?
3. How many tonnes of CO2 do Ontarians contribute to the atmospere? Where does this rank in emissions from other countries of the world?

OVERVIEW: A CLIMATE CHANGE INTEGRATED FRAMEWORK is used to consider anthropogenic or human-caused climate change. that is to design the scenarios.

Note: A fully integrated assessment of climate change was not achieved. All components have not linked dynamically. Further research is needed!!

OVERVIEW of Working Group 1 – WG1- Scientific Basis for the Technical Summary about the climate system and its relationship at the beginning of the twenty-first century.



1. What climate changes have occurred? Observations – Paleo and Instrumental periods Temperature, precipitation, snow/ice cover, sea-level, circulation, extremes.

2. How well are the past and present climates understood? – Observations and simulations

3. What changes could lie ahead? Simulations- natural variation, forcing agents, global climate, regional climate high impact events, stabilization.


The scientists have graded their answers to the questions as to the percentage chance that the answer is true. The precautionary principle is used here.

Confidence Code for Working Group 1 – The scientific basis of climate change:

>99% chance it is true =virtually certain
> 90-99% =very likely
> 66-90%=likely
> 33-66%=medium likelihood
> 10-33%=unlikely
> 1-10%=very unlikely
> 0-1%=exceptionally unlikely


Scientists must report the degree of reliability of their measurements. The reliability of measurements is the degree of confidence or certainty that is implied in all their measurements.For example, if a thermometer calibrated in tenths of degrees shows a reading of 37.5 oC, the reliability or certainty of measurement would be shown as 37.5 + 0.5 oC.

For the scientists in IPCC, the percentage chance of certainty or estimate of confidence is generally shown as a scale of likelihood.

Example: 90-99% chance =extremely likely, 66-90% chance=likely.

Improved climate change models* include more variables and larger base data periods which increase the confidence level.

ACTIVITY 4 Reliability of data and level of confidence.

Measure the height of another student.

1. List 5 variables which could influence the height measured and recorded.
2. What degree of certainty does this measurement have?
Remeasure eliminating at least 2 of the variables. Repeat this reading 3 times.
3. What are the results? What is the level of confidence in this data? Have another student repeat these measurements.

ACTIVITY 5 Research

What do precision and accuracy mean in measurements?