The ABCs of Global Climate Change

A briefing by the Canadian Association of Physicians for the Environment summarizing 2015 International Panel on Climate Change findings regarding the causes, impacts, and mitigation strategies for global climate change.

• The International Panel on Climate Change reported that human activity has caused greenhouse gas (GHG) emissions to reach levels higher than any other period in human history, with atmospheric concentrations higher than at any time in the last 800,000 years. It is considered "extremely likely" that these emissions and deforestation have been the primary drivers of global warming since the mid-20th century. In 2010, human activity emitted approximately 49 Gigatonnes (Gt) of GHGs, with over 75% resulting from industrial processes and fossil fuel combustion.
• Climate change has already led to increased heat-related deaths, a doubling of heat waves in certain areas, higher risks of flooding and extreme precipitation, and increased sea levels and storm surges since 1970. Future projections for the 21st century suggest more extreme impacts, including ocean acidification, melting glaciers and permafrost, increased extinction risks for flora and fauna, and threats to food and water security and human displacement.
• The severity of future climate risks depends on emission reductions and the protection of carbon sinks. Risks are expected to be moderate to high if temperatures rise by 1 to 2 degrees, and severe if they rise by 4 degrees relative to pre-industrial levels. To limit the increase to 2 degrees, annual GHG emissions must drop by 40 to 70% of 2010 levels by 2050; to limit it to 1.5 degrees, reductions of 70 to 95% are required by 2050.
• To achieve climate stability, the International Panel on Climate Change suggests increasing the share of low-carbon electricity (such as wind, solar, and hydroelectricity) from roughly 30% to over 80% by 2050. This involves phasing out coal and fossil fuels, improving energy efficiency, and changing behavior to lower demand. Such transitions offer co-benefits, such as improved air quality and increased physical activity from bike lanes and public transit, which outweigh potential adverse effects.

APA

Perrotta, K. (2016). The ABCs of Global Climate Change. Canadian Association of Physicians for the Environment. https://cape.ca/the-abcs-of-global-climate-change/

Chicago

Perrotta, Kim. The ABCs of Global Climate Change. Canadian Association of Physicians for the Environment, 2016. https://cape.ca/the-abcs-of-global-climate-change/.

Wikipedia

{{cite report |last1=Perrotta |first1=Kim |title=The ABCs of Global Climate Change |publisher=Canadian Association of Physicians for the Environment |date=17 February 2016 |url=https://cape.ca/the-abcs-of-global-climate-change/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{perrotta2016abcs, author = {Perrotta, Kim}, title = {{The ABCs of Global Climate Change}}, institution = {Canadian Association of Physicians for the Environment}, year = {2016}, month = feb, url = {https://cape.ca/the-abcs-of-global-climate-change/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }