Chapter 8 Review Questions

F (see “Cryosphere”)

T (see “Subsequent Conferences”)

F (see “Paris Agreement”)

T (see “Subsequent Conferences”)

T (see “Carbon Tax in British Columbia”)

T (see “Modelling Climate Change”, Box 8.3)

F (see “Nature of Climate Change”)

F (see “Agriculture”)

F (see “Provincial Responses”)

The weather is the sum total of atmospheric conditions for a short period of time. It is the momentary state of the atmosphere. The four main elements of weather are (1) temperature and (2) precipitation and humidity, and, to a lesser degree, (3) winds and (4) air pressure. Climate, on the other hand, is a composite or generalization of the variety of day-to-day weather conditions. It is not just “average weather,” because the variations from the mean, or average, are as important as the mean itself. Climate includes factors such as expected seasonal shifts and the range of expected extremes (e.g., extremes in temperature and precipitation).

(see “Nature of Climate Change”)

Climate change is defined as a long-term shift or alteration in the climate of a specific location, a region, or the entire planet. A shift could be measured for variables associated with average weather conditions, such as temperature, precipitation, and wind patterns (velocity, direction), and the expected variability of climate. In contrast, global warming addresses changes only in average surface temperatures. It does not address whether conditions are becoming wetter or drier, for example.

(see “Nature of Climate Change”)

Natural events, such as the eruption of large volcanoes, and changes in ocean currents, such as El Niño, influence climate. Volcanoes do this when they eject large quantities of dust and sulphur particles into the atmosphere as they erupt, reducing the amount of solar radiation reaching the surface of the Earth. El Niño is a marked warming of waters in the eastern and central portions of the tropical Pacific as westerly winds weaken or stop blowing, which leads to weather changes in over two-thirds of the globe, causing droughts and extreme rainfall. (see “Nature of Climate Change”)

The discussion of scientific evidence related to climate change is focused on warming, greenhouse gas emissions, glacial ice and snow cover, and sea level rise. The world is warming. Warming greater than the global average has already been experienced in many regions and seasons, with average warming over land higher than over the ocean. Greenhouse gas levels have been rising for several decades, and the concentrations of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) are at higher concentrations now than at any time over the past 3 to 5 million years. The 2017/2018 hydrological year was the thirty-first consecutive year in which glaciers lost more mass than they gained. In many areas of the world, reduced snow cover has been documented, as well as earlier spring melting of ice on rivers and lakes. Loss of permafrost in northern regions is also of concern, due to carbon and CH₄ emissions released from melting permafrost, along with substantial environmental and socio-economic impacts. The rate at which sea level is rising has been increasing.
(see “Scientific Evidence Related to Climate Change”)

Rising sea levels threaten coastal environments such as wetlands, whose presence is regulated by water levels, and bluffs and beaches, which will be impacted by increased erosion by waves. Groundwater will become more susceptible to contamination by saltwater, and structures along coast, such as wharves, roads and buildings, will be at greater risk of flooding and damage.
(see “Sea Level Rise”)

All climate models consider some or all of five components in order to predict future climates:

• Radiation: incoming (solar) and outgoing (absorbed, reflected) energy
• Dynamics: the horizontal and vertical movement of energy around the globe
• Surface processes: the effects of the Earth’s surface (snow cover, vegetation) on climate (i.e., albedo, emissivity)
• Chemistry: the chemical composition of the atmosphere and its interactions with other Earth processes (i.e., carbon cycling)
• Time step and resolution: the time scale of the model (minutes or decades) and the spatial scale of the model (your backyard or the entire globe)
  (see “Climate Models”)

Atmosphere-Ocean General Circulation Models (AOGCMs) - The most extensively used types of models in understanding the dynamics of the climate system, including interactions among the atmosphere, oceans, land, and sea ice. This information is then used to make predictions about the impacts of increased GHG concentrations. These models are often used to examine seasonal to decadal climate projections.

Earth-System Models (ESMs) - The current state-of-the-art modelling approaches, which provide the most comprehensive tools for simulating future responses of the climate system. ESMs expand on AOGCMs to include the interactions of biogeochemical cycles, such as the carbon cycle, the sulphur cycle, and ozone.

Earth-System Models of Intermediate Complexity (EMICs) - A more simplified version of the ESM, EMICs include relevant components of the Earth-system, but often at a lower resolution or in a more simplified form compared to ESMs and AOGCMs. However, these models sometimes include factors not yet incorporated into ESMs, such as the role of ice sheets in the global climate system. These models tend to be applied to long-term, millennial time scales.

Regional Climate Models (RCMs). Limited-area models which allow for “downscaling” of global climate model simulations to particular geographic regions, providing more detailed information. RCMs usually include land–atmosphere interactions, but often exclude oceanic and sea ice considerations.

(see “Climate Models”)

Criticisms centre around four key points:

• No legally binding emission targets
• Lack of specificity on financial support
• No liability provision
• No changes in policy premises
  (see “Paris Agreement”)

There is strong scientific consensus that the increase in greenhouse gases has been caused by human activities. The concentrations of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) are at higher concentrations now than at any time over the past 3 to 5 million years. The last time Earth experienced a comparable concentration of CO₂, “the temperature was 2–3°C warmer and sea level was 10–20 metres higher than now.” During the period 1970–2010, 78 per cent of total GHG emissions came from combustion of fossil fuels and industrial processes.

Most adaptation responses fit under the following broad categories:

• “No-regrets”: Actions that provide benefits regardless of impacts incurred from climate change
• Profit/opportunity: Actions that take advantage of a changing climate to yield net benefits
• “Win-win”: Actions that reduce vulnerability to climate change while also contributing to other economic, social, or environmental goals (including reduction of greenhouse gas emissions)
• Low-regret: Measures that have relatively low costs and yield high benefits
• Avoiding unsustainable investments: Measures that limit or prevent new investment in areas already at high climate risk and where climate change is likely to exacerbate the impacts
• Averting catastrophic risk: Policies or actions taken to avoid unacceptably high losses as a result of climate events

Incremental adaptation builds on existing, conventional programs, strategies, and approaches to improve performance and efficiency. This could include enhancing coordination between government agencies, improving flood-wall protection structures, enlarging water reservoirs, or improving disaster warning systems. However, due to the nature of climate change, improving existing approaches may not be sufficient in the future. Some changes may require fundamentally different approaches and systems to prepare for future climate risks. This is referred to as transformative adaptation.

(see “Adaptation”)

The four communication challenges relate to the following:

Several key reasons why communicating climate change is challenging:

• Global climate change is a complex issue.
• Uncertainties exist regarding almost every aspect of the climate change issue, and these uncertainties increase when moving from natural to human systems
• The impacts of climate change will be disproportionately heavier on people in less developed countries and on future generations.
• The basic causes of climate change are embedded in current values and lifestyles.

Some ways to improve climate change communication:

• Framing the message in a way that resonates with target audiences.
• Highlighting the existence of scientific consensus over the fundamentals of climate science.
• Recruiting credible messengers and spokespersons for diverse audiences.
  (see “Communicating Climate Change”)

Tactics used by climate change deniers:

1. Because cause-and-effect relationships are difficult to establish, until clarification is achieved it is inadvisable to develop regulations. The real intent is to create doubt in the minds of citizens and policy-makers, with the result that introduction of regulations will be postponed (parallels to tobacco industry).
2. Well-funded organizations create what appear to be grassroots criticism of climate change science.
3. Assembling results of surveys of researchers critical of climate change science.
   (see “Climate Change Deniers”)

Terrestrial systems: Changes in species range (e.g., birds, trees), phenology of many terrestrial species (leading to a phenological mismatch between predator and prey), breeding habitats (e.g. polar bears, marmot) are likely to occur.

Agriculture: One of the major limitations on agricultural activity in most areas of Canada is our cold climate. A positive gain could occur in some regions, since it would extend the growing season, allow the growth of certain crops to expand northward, lengthen outdoor feeding seasons for livestock, and reduce the damage from severe cold or frosts. On the negative side, however, challenges also may arise in some regions and sectors. Many plants are vulnerable to heat stress and drought, and if temperatures increased appreciably or water became limited, crops could be adversely affected. New pests and diseases and increased growth of weeds may also threaten agricultural productivity.

Marine and freshwater systems: Every part of Canada except the southern Prairies has become wetter. Generally higher temperatures cause higher rates of evapotranspiration, increasing surface drying and more moisture in the air. This can lead to variability in streamflow of rivers and in lake levels. Fish are vulnerable to changes in temperature, precipitation, wind patterns, and chemical conditions in or related to aquatic systems. These changes could also impact agriculture, fisheries and shipping seasons.

Cryosphere: Warmer temperatures in higher latitudes are expected to cause melting of ice. Arctic sea ice is also decreasing. In the Arctic, much of the multi-year ice has been replaced with first-year ice that melts completely during the summer. One outcome is the easier passage to the Northwest Passage – concerns over sovereignty and impacts of shipping. Another consequence will be degradation of permafrost in both alpine and high-latitude regions. As well, reduced ice cover and degradation of permafrost would reduce the expansive and stable frozen surface that northerners count on for winter travelling as well as for hunting and other traditional activities.

Ocean and Coastal Systems: Both sea temperatures and sea levels are rising. Changes are also likely to have significant impacts on the chemical composition of oceanic waters.

Health and Infectious Disease: Canadians can expect a greater incidence of disease and health impacts.

(see “Implications of Climate Change in Canada”)

Canada ratified the Protocol under a federal Liberal government in 2002 and was to reduce greenhouse emissions to 6 per cent below 1990 levels by between 2008 and 2012. However, shortly thereafter, US President George W. Bush stated that the United States would not sign the Kyoto agreement, and would instead use a “voluntary approach,” with the purpose of reducing “greenhouse gas intensity” by 18 per cent over 10 years. Former Canadian Prime Minister Harper believed it would be economically foolish to accept the Kyoto Protocol targets when the nation with the largest economy had decided not to do so. Upon becoming prime minister in 2006, Harper indicated that Canada’s Kyoto commitment was unrealistic and unachievable. He also noted that if Canada were to remain economically competitive with its largest trading partner, the United States, it would be unwise to reduce GHG emissions unless and until the US had also accepted a binding target to reduce GHGs. Canada formally pulled out of the Kyoto Protocol in 2011, when emissions had already increased by some 20 per cent over the 1990 base set by Kyoto.

(see “Kyoto Protocol”)

Regarding mitigation strategies, a mix of options exist to reduce atmospheric carbon concentrations including carbon taxes, cap-and-trade systems, carbon sequestration, new technologies, and geo-engineering.

Carbon tax: tax is applied either on emissions produced by a company or organization, usually by the tonne, or on products and services that significantly contribute to emissions, such as gasoline.

Cap-and-Trade Systems: government sets a limit on the amount of GHG emissions allowed by industry, often reducing the limit each year in order reach a specified target. Emitters that exceed allowed emission levels, or quotas, need to purchase emission quotas from emitters that fall short of their allowed quota.

Carbon sequestration: carbon can be sequestered in biological sinks. Land-use practices that encourage agricultural crops and forest systems with the capacity to sequester carbon have been endorsed as a legitimate way for nations to achieve GHG targets.

New Technologies: these include finding alternatives to fossil-fuel combustion for heating buildings, running manufacturing and industrial equipment, and powering vehicles, aircraft, and ships.

Geo-engineering: reducing global warming through systematic large-scale manipulation of the Earth’s climate such carbon sequestration by direct (capture of carbon dioxide air) or indirect (iron fertilization of oceans) approaches. Another approach is management of solar radiation, such as by producing stratospheric sulphur aerosols, or using space mirrors and enhancement of cloud reflectivity.

(see “Mitigation”)

The greenhouse effect describes the role of the atmosphere in insulating the planet from heat loss, much like a blanket on our bed insulates our bodies from heat loss. The small concentrations of greenhouse gases within the atmosphere that cause this effect allow most of the sunlight to pass through the atmosphere to heat the planet. However, these gases absorb much of the outgoing heat energy radiated by the Earth itself and return much of this energy back towards the surface. This keeps the surface much warmer than if they were absent. This process is referred to as the “greenhouse effect” because, in some respects, it resembles the role of glass in a greenhouse.

(see “Nature of Climate Change”)