Lecture 4 - Climate Change & Extreme Weather

Weather

The weather is the condition of the atmosphere in one area at a particular time

Climate

The weather conditions prevailing in an area in general or over a long period

Major Elements of Weather & Climate

• Temperature

• Air

• Pressure

• Wind

• Solar energy

• Humidity

• Precipitation

• Topography

Ocean Currents

• Regulate climate

• Counteract uneven distribution of solar radiation

• Transport warm weather to poles and cold weather to tropics

• No currents would result in extreme weather and inhabitable land

Thermohaline Circulation

Conveyor belt of water

Brings warm, shallow water to cold areas

The North warms faster than the rest of the world

Cold water sinks

Natural Phenomena: El Nino

• Heavier winter precipitation
• Caused by a warm ocean current of
varying intensity that usually occurs after late December
• Starts in the Pacific Ocean along the
coast of Ecuador and Peru
• Results in fewer hurricanes but more tropic storms • Unusually hot and dry weather

Natural Phenomena: La Nina

• Unusually cold ocean temperatures in the equatorial Pacific

• La Niña's cooling of the equatorial Pacific tends to favor hurricane
  formation in the western Atlantic

• Brings colder winters to the Canadian West

Greenhouse Effect

• The passage of longwave radiation into space is delayed as the atmosphere absorbs radiation before it can escape (natural, yet bad in excess)

• Keeps Earth warm and stabilizes the sea level

Caused by: Global warming, Ocean acidification, Air pollution, Ozone depletion, Smog

Global Warming

• The Earth cools down by giving off infrared radiation

  Before infrared radiation can escape, greenhouse gases absorb it, warming the Earth

Temperature Anomaly

Departure from the long-term average temperature

• Positive Temperature anomaly: Temperature is above average value

• Negative temperature anomaly: Temperature is below average value

Atmosphere gases

Nitrogen and Oxygen

the ocean is the greatest natural source of carbon dioxide

Global Warming Potential (GWP)

There has been slow warming since the last ice age

• GWP is the relative measure of how much heat a greenhouse gas traps in the atmosphere

• It compares the amount of heat trapped by a certain mass gas to the amount of heat trapped by a similar mass of carbon dioxide

• The most GWP comes from fluorocarbons

Carbon dioxide is the reference gas

Human Sources of Green House Gases

Human sources of CO2 are much smaller than natural emissions but they upset the balance in the carbon cycle that existed before the Industrial Revolution

Sources of Green house Gases

• Burning fossil Fuels

• Deforestation

• Intensive livestock farming

• Use of synthetic fertilizers

• Industrial processes

Paleoclimatology

Proxy measures of historical climate change

• Ice cores

• Coral reefs

• Ocean sediments

• Pollen analysis

• Tree rings

• Historical records

Ice Cores

• Located high in mountains and deep in
  polar ice caps

• Scientists drill through the deep ice to
  collect ice cores

• Contains dust, air bubbles, and isotopes of oxygen, that can be used to interpret the past climate of that area

  
  

Kneeling Curve

• A graph that plots the ongoing change
  in concentration of carbon dioxide in Earth's atmosphere since 1957

• Comes from the Mauna Loa Observatory in Hawaii

Impacts of Climate Change

• Rising global temperature

• Melting of Arctic & Antarctic Sea ice

• Melting glaciers

• Rising seas levels

• Changes in Frequency and Intensity of Extreme Weather Events

• Changing Precipitation Patterns

Most melting occurs in the West Antarctica Peninsula

Sea level Rise

• Sea-level changes are driven by a combination of local, regional, hemispheric or global factors

• Arctic ice is melting (Glacial melting)

• Warming of the ocean causes the water to expand (Thermal expansion)

The changing volume of the oceans is due to
thermal expansion, glacial melting and
glacio-isostatic activity (Ongoing vertical movement of land due to weight of ice sheets deforming)

Ocean deoxygenation

Loss of oxygen in oceans due to climate change.

As oceans get warmer, their ability to trap dissolved oxygen decreases

Cold water contains a lower concentration of gas

Ocean Acidification

• When carbon dioxide dissolves in the ocean, carbonic acid is formed

• This leads to higher acidity, mainly near the surface, which has been proven to inhibit shell growth in marine animals and is suspected as a
  cause of reproductive disorders in some fish

Permafrost melting

Thick organic layer on top of permafrost, causes the ground to destabilize

Changes in Frequency and Intensity of Extreme Weather Events

Results in:

• Rising # of hurricanes

• Rising # of tornadoes

• Rising # of rare ice storms

• Mid-latitude polar vortex

• Droughts

• Dramatic increase in # of floods

• Jet streams

Mid-latitude polar vortex

• The counter clockwise flow of air, keeping it near the poles

• It is a large area of low pressure, cold air surround the poles

• Weakens in summer, strengthens in winter

Jet Streams

Though it's a relatively new area of study, there's increasing evidence that suggests this phenomenon will happen more often and become more extreme

• Narrow fast band of air in the uppermost atmosphere

• moves weather patterns

Climate Change & The Polar Vortex

A recent Intergovernmental Panel on Climate Change (IPCC) report found the Arctic is warming two to three times faster than anywhere else on Earth. This temperature difference upsets the stability of the jet stream.

Changing Precipitation Patterns: Drought & Desertification

• Canada’s arctic experiences periods of drought and heavy rainfall

• Major downpours are the result of humans exhausting the soil and climate change

Responding to climate change

• Mitigation (reduce emissions & enhance carbon sinks)

• Adaptation

• Both

Forests as carbon sinks

• Most reliable carbon sink globally

• Increase urban forest

• replant clear-cut areas

International Efforts to Fight Climate Change

1992 United Nations Framework Convention on Climate Change

• An international treaty that acts as a framework for international cooperation to combat climate change by limiting average global temperature increases and the resulting climate change, and coping with impacts that were, by then, inevitable.

A convention is weaker than a protocol

Kyoto Protocol (1997)

• The only nations that did not sign are Afghanistan, Sudan & the U.S.A.

• At the time, it was the closest thing we had to a working global agreement to fight climate change

• A top-down process where countries got together and set targets for emission reductions, binding for developed countries only

Flaw of Kyoto Protocol

• Canada did not sign second commitment agreement because most nations reduced emissions but did not meet targets

Paris Agreement (2015)

• More countries signed because it is a bottom-up approach

• First-ever universal, legally binding global climate deal

• Some elements of the agreement — such as requirements to report on
  progress towards lowering emissions — are binding. However, some elements are non-binding, such as the setting of emission-reduction targets

• Importing climate change into everyday policies

  
  

Carbon footprint

the total set of greenhouse gas emissions caused by an individual, event, organization, or product, expressed as carbon dioxide equivalent

Actions at the municipal level

• Solution to global problems are rooted at the municipal level

• In line with Paris Agreement

• Cities adopt policies to implement climate change measures