Climate Change

Climate Change

“How could I look my grandchildren in the eye and say I knew what was happening to the world and did nothing?”
David Attenborough


What is climate change?

The earth’s temperature is determined by heat radiation. The temperature increases when the amount of heat energy absorbed by the earth is greater than the amount of heat reflected.

Short-term changes in temperature are only regional weather patterns and should not be confused with climate change. A long-term pattern extending for at least 30 years is required to show a climate trend. The global temperature on earth has been increasing for over 100 years, indicating a change in climate is in progress.

Several natural factors affect the climate:

  • the amount of heat energy emitted by the sun
  • the distance between the earth and the sun
  • the angle of the sun’s rays striking the earth
  • the action of ocean currents
  • volcanic emissions blocking the sun’s rays


The Problem

We are growing our population, destroying habitat, undermining climate stability, and depleting resources in ways and at rates that cannot be mitigated by any new tool or energy source.
—Richard Heinberg


What is happening now?

The global temperature is rising at a rate and to a level that cannot be explained by any combination of natural causes. Temperature changes occurring in the past took thousands of years and do not compare to the present rapid increase.

Global temperature

Global surface temperature relative to 1880–1920 based on GISTEMP analysis (mostly NOAA data sources, as described by Hansen, J., R. Ruedy, M. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., 48, RG4004. We suggest in an upcoming paper that the temperature in 1940-45 is exaggerated because of data inhomogeneity in WW II. Linear-fit to temperature since 1970 yields present temperature of 1.06°C, which is perhaps our best estimate of warming since the preindustrial period.
James Hansen and Makiko Sato (2016).

Why is the temperature increasing?

  • The burning of fossil fuels has created a huge accumulation of CO2 in the atmosphere, trapping heat near the surface of the earth.
  • The amount of CO2 is still increasing as a result of rapid industrial growth and a rising global population.
  • Widespread deforestation has added to the imbalance of the atmospheric composition by removing a natural reservoir for the excess CO2.

The Intergovernmental Panel on Climate Change (IPCC) and every major scientific research organization have projected temperature increases during the 21st Century. Unless a significant reduction in the use of fossil fuels occurs soon it is very unlikely the global temperature can be held to a 2 degrees Celsius rise, a level considered as the upper limit of safety. The heavy emphasis on economic growth and the continued demand for coal, oil, and natural gas indicate a likely temperature increase ranging from 2 to 6 degrees Celsius this century.

What is the expected impact if the global temperature continues to rise?

  • The climate is warming at a rate that severely challenges the ability of all life forms, including humans, to adapt to a rapidly changing world. The scale of the problem is intensified by the failure to take prompt action.
  • The greatest temperature increase is occurring in the polar region, causing rapid melting of Arctic sea ice, ice sheets, and glaciers. The melting of ice sheets and glaciers and thermal expansion of water are causing global sea levels to rise. Expectation of further rising is threatening heavily populated low-lying coastal areas.
  • Rising temperatures are leading to extreme weather conditions including droughts, heat waves, and more precipitation, floods, and storms. These increasingly frequent and severe events produced by climate change are already causing crop failures, regional water shortages, soil erosion, wildfires, human health issues, and spiralling costs of damage repairs.
  • Humans require healthy and diverse ecosystems for life-support. Rising temperatures, degradation of ecosystems, and habitat loss are causing the rapid extinction of countless species. Competition for resources is accelerating the decline in biodiversity.
  • The excess CO2 produced by warming temperatures is causing the acidification of the oceans, a condition that is destroying coral reefs and will prevent marine organisms from building protective shells. Many marine species are facing extinction. Acidification will eventually result in the loss of a vital source of human food supply.
  • Melting permafrost is a two-edged sword. Buildings and roads constructed on surfaces that were believed to be frozen permanently are sinking. The melting permafrost will allow methane, a greenhouse gas twenty times more powerful than CO2, to escape and amplify the warming of the climate.
  • The cost of dealing with the financial burden created by these impacts could be enormous. Delays in planning for the continuing rise in global temperature will magnify the cost. New standards for buildings, bridges, and other parts of the infrastructure are required. Agricultural products need to be modified to meet shifting climate zones. Preparation for sea level rise is essential for the protection of populated low-lying areas. Funding for storm damage will be needed. Insurance costs will rise as repair costs mount.


What will be the final outcome?

In addition to climate change, several other critical conditions, all caused by human activity, have increased or persisted in recent decades.

  • Population growth and poverty
  • Failing states experiencing political and economic instability
  • Depletion of renewable and non-renewable resources
  • Degradation and pollution of the earth’s surface, oceans, and atmosphere
  • Biodiversity loss and breakdown of ecosystems

Individually each of these conditions presents challenges capable of a drastic impact on human wellbeing. Together they will probably be beyond the scope of human management. If the present conditions continue, the inhabitants of this planet will be faced with a disastrous combination of overpopulation, huge areas of uninhabitable land, millions more people in poverty, high mortality rate, civil unrest, survival conflicts over food and water, personal security loss, a breakdown of law and order, and ultimately, economic and environmental collapse.

Projected sea level rise from 1990 to 2100. Actual observations of annual global sea level rise over the past half century (red line), relative to 1990. Source: NRC 2010.


    Why is there still a debate about the cause of climate change?

    • The “debate” stems from the large information gap between what is known by the scientific community and what is understood by the public.
    • There is a strong consensus among the scientists. At least 95% of the scientists who work in the field agree that human activity is mainly responsible for climate change.
    • Public recognition of the consensus reached by the scientists is impeded by special interest groups that promote the continued use of fossil fuels. They are conducting a relentless campaign designed to create public doubt about the science of climate change. Vested interests have overwhelmed ethical principles. Many of these lobby organizations receive funding from corporations with vested interests in maintaining the status quo to assist them with their tactics.


    “It’s in the interests of some of the most powerful players on earth
    to prolong the status quo. Some of the players are countries
    and some are companies.”
    —Bill McKibben


    How do we know who to believe?

    • Scientists build their credibility by regularly publishing peer-reviewed research papers in leading journals and by receiving substantial numbers of citations, demonstrating the value of their work.
    • Advancements in science are derived from the ongoing interaction from thousands of papers where each new piece of knowledge adds to our understanding of the planet.
    • It is in the best interests of everyone to rely on the scientists who have made the most contributions to the research in climate change and disregard those without evidence of their expertise.


    “It’s important to listen to what the scientists have to say, even when it’s inconvenient, especially when it’s inconvenient.”
    — Barrack Obama


    The Solution

    “There are no passengers on Spaceship Earth. We are all crew”
    —Marshall McLuhan

    The policy of economic growth so widely promoted by economists for years is not sustainable. A growing population and increasing consumption have overreached the ability of the planet to meet human requirements. There is ample evidence we must abandon our collision course with nature and reduce the demands on a finite planet. The present system of perpetual economic growth now faces a barrier that cannot be overcome by more technical innovations.

    The single inescapable solution is to reduce our dependency on the use of fossil fuels, the prime mover of economic growth and greenhouse gas emissions, and supply our needs with renewable energy sources. It is the only way the global temperature level can be held in check. This goal can be achieved by establishing an international legally binding agreement with firm targets and timelines. At present, the majority of the public views the danger of climate change as a distant possibility, not as an imminent threat. It is up to government leaders to speak openly and clearly about the need for immediate action if the threat of climate change is to be averted. In Canada, the government doesn’t allow scientists to speak to the media on environmental issues without prior approval of the content.

    Objections to reducing the use of fossil fuels must be countered with the realization we have no viable option. We cannot go down the path of emission-producing fuels without leaving future generations in a situation beyond their control. Failure to act on a potentially fatal situation of our own making is the equivalent of gambling with the lives of our grandchildren. A huge majority of the world’s leading climate scientists tell us we are faced with a rapidly advancing global crisis. The steps we need to take present a significant challenge, but they are only an inconvenient problem when compared to the extreme danger of pursuing the current “business as usual” approach.

    “We have assumed responsibility for the planet. How will we manage it?
    —James Lovelock


    Websites, Books and Articles

    General: RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists. Go to “Start here”, a section for beginners and a list of frequently asked questions; Go to “Index” for comprehensive lists covering every aspect of climate change science. A very comprehensive source of reliable information.

    Skeptical Science explains climate change science and rebuts misinformation spread by deniers.

    Desmogblog: A source of current political and scientific information on climate change with regular updates; See “Research Data” for information on climate change dissenters.

    Paleontology: Wunderground has some excellent information on Climate change past and present. Scroll down for other topics. See “Resources” in the sidebar.

    History: The American Institute of Physics offers an excellent account of the history of climate change research from the mid 20th century.

    Sea level rise: A 2012 report explaining the rise in sea level is exceeding the 2007 IPCC projections.

    Arctic melting: A good description of the implications of melting sea ice, ice sheets, and glaciers.

    Atmospheric CO2 data and trend tracks the amount of CO2 in the atmosphere.

    Deforestation: Why deforestation is causing severe problems with implications for climate change.

    Acidification: Describes the harm to marine life and coral reefs as the ocean becomes more acidic from excess CO2.

    Biodiversity loss: Explains why biodiversity loss, damage to ecosystems, and species extinction is a global threat.

    Extreme weather: James Hansen explains the connection between climate change and extreme weather conditions.

    Human health: Discusses the impact of climate change on human health.

    Tar Sands and Climate: An excellent article by James Hansen, world renowned climate scientist about Canada’s tar sands and climate change. “If Canada proceeds [to exploit the oil in its vast tar sands reserves], and we do nothing, it will be game over for the climate.”

    Climate Scientists: James Prall’s University of Toronto website displaying thousands of scientists with their contributions to climate change research. See also, James Prall et al’s Proceedings of the National Academy of Sciences paper on “Expert credibility in climate change

    Scientific Organizations: A comprehensive list of major scientific organizations with opinions on the cause of climate change.


    Storms of My Grandchildren by James Hansen. 2009 Bloomsbury USA, New York
    An explanation of the grave danger caused by climate change and the obstacles preventing the urgent action required to avoid disaster.

    Keeping Our Cool by Andrew Weaver. 2008 Penguin Canada
    An account of the scientific evidence revealing human activity as a major cause of climate change and the action we must take to avert catastrophe.

    Generation Us
    by Andrew Weaver. 2011 Orca Books, Victoria B.C.
    A short simplied explanation of climate change designed as a starting point for those new to the topic.

    Climate Cover-Up by James Hoggan. 2009 Greystone Books, Vancouver B.C.
    An analysis of a powerful propaganda machine designed to create public uncertainty about climate change.


    An interesting presentation on the need to take action
    to combat climate change

    An 18 minute video presentation by James Hansen, famous climate scientist

    A 10 minute video with a technical explanation of global warming

    An excellent short video describing the danger of sea level rise

    Global Warming, What You Need To Know


    Hansen, J., Mki. Sato, R. Ruedy, K. Lo, D.W. Lea, and M. Medina-Elizade, 2006: Global temperature change. Proc. Natl. Acad. Sci., 103, 14288-14293
    NRC (2010). Advancing the Science of Climate Change. National Research Council. The National Academies Press, Washington, DC, USA.

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