Dr. Ariful Bari Chowdhury

Lecturer, NSU

Climate Change and Its Impact on human health

Atmosphere

• The atmosphere is the thin layer of gases that envelops Earth.

• The atmosphere is composed of gas molecules held close to Earth's surface by a balance between gravitation and thermal movement of air molecules (90% of the weight of the atmosphere is in the first 12 km above the surface of the Earth).

Atmosphere Composition

• Major gases in the atmosphere are nitrogen (78%), oxygen (21%), argon (0.9%), and carbon dioxide (0.03%).

• The atmosphere also contains trace amounts of numerous elements and compounds, including methane, ozone, hydrogen sulfide, carbon monoxide, oxides of nitrogen and sulfur, hydrocarbons, chlorofluorocarbons (CFCs), and various particulates or aerosols (small particles).

• Water vapor is also present in the lower few kilometers of atmosphere.

Atmospheric Processes• Atmospheric pressure is the weight of overlying

atmosphere (air) per unit area; it decreases as altitude increases because there is less weight from overlying air. At sea level, atmospheric pressure is 10 N/m2 (newtons per square meter), which is equivalent to 14.7 lb/in2.

• Water vapor: In the lower atmosphere, water vapor content varies from approximately 1% to 4% by volume. The amount of water vapor present in the atmosphere at a particular location depends on many factors

• Saturation point or dew point: When air holds the maximum amount of water at a given conditions.

• Relative humidity is a measure of how close the air is to saturation.

Ozone in Nature• Ozone is an important natural component of

the stratosphere.• Ozone is concentrated in a layer 12-16 miles

(20-25 km) above sea level.• It is formed when high-energy ultraviolet

radiation splits normal oxygen (O2).

Schematic representation of the formation of stratospheric ozone.

•It shields the earth from UV ray

Chlorofluorocarbons• Chlorofluorocarbons (CFCs) were developed

in the 1920s as a new class of chemicals that were safe, non-flammable, stable, and nonreactive.

• These chemicals were very useful for industry.

• The CFCs were considered ideal for– Refrigeration and air-conditioning equipment– Nontoxic propellants for aerosol cans– Blowing agents for plastic foams– Solvents and cleaning agents in the electronics

industry

Chlorofluorocarbons and the Ozone Layer

• The stability of CFCs in the lower atmosphere permits them to diffuse up to the stratosphere.

• In the stratosphere, ultraviolet radiation breaks down the CFC molecules, releasing atomic chlorine.

• The chlorine atoms react catalytically with ozone, converting it into normal O2 oxygen.

• One chlorine atom may destroy between 10,000 to 100,000 ozone molecules before being washed out of the atmosphere.

• CFCs threaten the very existence of life on our planet.

Human Response to Ozone Depletion

• In the 1970s, Molina and Rowland’s prediction of damage to the ozone layer led to the reduction of use of CFCs as aerosol propellants.

• Confirmation of the Antarctic ozone hole and subsequent discoveries have led to a series of international agreements to reduce the damage:– Montreal Protocol– London Amendments– Copenhagen Agreements

• The current situation is that the ozone depletion problem will continue to get worse for decades to come because of the long atmospheric lifetime of CFCs that have already been produced and emitted.

Effects of Increased Ultraviolet Radiation

• A small amount of UV radiation is healthy for humans and other organisms

• For every 1% decrease in the ozone layer, the intensity of UV-B radiation on the Earth’s surface increases 2%.

• Increased UV-B radiation can cause several problems:– Increases in skin cancer rates– Increases in cataracts and other eye diseases– Widespread ecosystem damage– Accelerated degradation and breakdown of

various plastics– Unpredictable climatic change

Greenhouse Effect

• The greenhouse effect is caused by atmospheric water and trace gases that reduce the rate at which Earth gives off infrared radiation.

• Without the natural greenhouse effect, the average global temperature would be about 1.4º F (-17º C).

• In recent Earth history, a relatively steady-state balance has maintained an average global temperature of 59º F (15º C).

Greenhouse Effect

(a) Greenhouse gases in the atmosphere allow in energy from the sun.

(b) Greenhouse gases trap or reflectlower-energy infrared radiation (heat)from the Earth's surface.

Greenhouse Gases

• Carbon dioxide is responsible for about 50% to 70% of the current abnormal global warming.

• Other greenhouse gases that play a significant role are;– CFCs– Methane– Nitrogen oxide

• While the other greenhouse gases are present in much smaller amounts than CO2, they are more effective in trapping the Earth’s heat radiation.

Carbon Emissions

• The major increase in atmospheric CO2 is from the burning of fossil fuels: coal, oil, and gas.

• Additional CO2 is emitted through deforestation, both through the burning and decay of wood, and the loss of trees, which can remove excess CO2 from the atmosphere.

World carbon emissions from fossil fuel burning.

Is Earth Warming Up?

• Over the last century there has been an increase in the atmospheric temperature at the Earth’s surface.

• Other data which support this trend are:– Ocean surface temperatures– Geophysical borehole temperature patterns– Retreat of nonpolar glaciers

• At the present time, the Earth is heating up more than ten times faster than it did at the end of the last Ice Age.

Intergovernmental Panel on Climate Change Statements

• “the balance of evidence suggests that there is a discernible human influence on global climate” (1995) 

• “human activities are modifying the energy balance of the planet” (1999)

• “with a high degree of confidence, most of the observed warming over the last 50 years is due to the increase in (anthropogenic) greenhouse gas concentrations” (2001)

Agricultural Failure

• United Nations Framework Convention on Climate Change (UNFCCC) claims climate change as one of the causes of food insecurity. – Regional temperature rises at high northern latitudes

and in the center of some continents;– Increased heat stress to crop and livestock; e.g.

higher night-time temperatures, which could adversely affect grain formation and other aspects of crop development;

– Possible decline in precipitation in some food-insecure areas such as southern Africa and the northern region of Latin America;

Agricultural Failure (Cont.)

– Increased evapotranspiration rates caused by higher temperatures, and lower soil moisture levels;

– Concentration of rainfall into a smaller number of rainy events with increases in the number of days with heavy rain, increasing erosion and flood risks;

– Changes in seasonal distribution of rainfall, with less falling in the main crop growing season;

– Sea level rise, aggravated by subsidence in parts of some densely populated flood-prone countries, displacing millions;

– Food production and supply disruption through more frequent and severe extreme events.

What type of storm is this?

•Increasing weather catastrophes•Tropical cyclones also increase because of global warming•Increasing number of category 4 and 5 hurricanes is directly linked to increasing temperatures

Extreme Weather

Ways to Combat Global Warming

• The principle ways are to cut down on CO2 emissions and provide additional sinks for CO2, such as increasing forest cover, fertilizing the ocean with limiting nutrients to promote the growth of phytoplankton to absorb CO2, and injecting CO2 in deep into the earth.

• Also, increasing energy efficiency and promoting the use of renewable forms of energy.

Energy types

• Non-renewable : – Oil, – Gas, – Coal, – Nuclear power

• Renewable : – Solar, – Hydropower, – Geothermal,– Biomass, – Wind, – Tidal, etc.

Necessary Steps for Prevention• Educate all the people about global warming• Technology transfer and Efficient Production system• Recycling • Encourage using renewable energy sources• Burning forests accounts for about 20% of anthropogenic

emissions of CO2 into the atmosphere. Management plans to minimize burning and protection of the forests would help reduce the threat of global warming.

• Planting more trees (reforestation) is also a potential strategy. Reforestation would increase sinks for carbon dioxide.

• Less packaging could reduce garbage significantly• Choose vegetarian or vegan meals

• Livestock are responsible for more greenhouse gas emissions than transportation

Global climate change: Impact on human health

State of the world’s health

• The profiles of health and disease vary greatly between regions and countries.

• Non-communicable diseases (such as cardiovascular diseases, cancer, and depression) predominate in developed countries.

• In poorer countries, infectious diseases (especially in childhood) remain important, even as non-communicable diseases increase in urban populations with changes in lifestyle and environmental and occupational exposures.

• This changing pattern of disease associated with development is called epidemiological transition.

State of the world’s health

• Similarly, the "risk transition" reflects changing patterns of environmental exposures from traditional (e.g. unsafe water and food, inadequate sanitation, and poor housing) to modern (air pollution, chemical exposures, motor vehicle accidents) exposures.

• Globally, infectious diseases remain a major cause of human morbidity, and are responsible for about one-third of all deaths

KEY IMPACTS RELATED TO CLIMATE CHANGE

• Climate variability and extreme weather events: Loss of life, shelter, food, water, sanitation, water born diseases, etc.

• Natural disasters: Flood, Drought• Vector-borne infectious diseases: Malaria, dengue,

dengue haemorrhagic fever • Food security• Water quality and quantity• Heat stress and air pollution• Social disruption: The IPCC noted that "the greatest

effect of climate change may be on human migration as millions of people will be displaced due to shoreline erosion, coastal flooding and agricultural disruption."

Climate variability and extreme weather events

• Rainfall events triggering mosquito-borne disease outbreaks;

• Rainfall events triggering a flood disaster;

• Rainfall events triggering contamination of the water supply with human or animal waste;

• Thunderstorms and high humidity leading to short-term increases in hospital admissions for respiratory and cardiovascular diseases;

• Heat-waves leading to heat-related illness and death.

Adaptation• Disaster preparedness and mitigation

• Weather forecasting, seasonal forecasting and early warning systems

• Monitoring and Surveillance

• Control of vector-borne and water-borne diseases

• National nutrition action plans

Adaptation to climate change and climate variability

• The primary objective of adaptation is to reduce disease burdens, injuries, disabilities, suffering and deaths.

• Many impacts of climate change - including health impacts - can be reduced or avoided by various adaptations

Disaster preparedness and mitigation

Classically there are four phases of disaster reduction• Mitigation: long term activities undertaken prior to impact

aimed at reducing the risk or occurrence and/or effect of a disaster; Impact and adaptation

• Preparedness: pre-disaster activities intended to increase the effectiveness of emergency response during a disaster;

• Response: activities undertaken immediately before and during an event, to protect lives and properties; and

• Recovery: post-disaster activities undertaken in order to return affected communities to a more normal condition

Kyoto Protocol

Back Ground• 1979 First World Climate Conference - first major international

forum to raise the alarm bells. • 1987 Montreal Protocol was the beginning of a successful

phase-out of ozone depleting chemicals, primarily CFCs, which are also greenhouse gases.

• 1988 Intergovernmental Panel on Climate Change established• 1990, the IPCC released its report giving scientific evidence of

climate change, and the UN General Assembly approved the start of treaty negotiations to deal with the problem of climate change.

• 1992 United Nations Framework Convention on Climate Change (UNFCCC) is the ‘parent’ treaty of the Kyoto Protocol. It was signed by 169 countries.

• 1995 First session of COP• COP – Conference of parties - “Parties” refers to Convention

signatories• 1997 Third session of COP in Kyoto…Kyoto Protocol

Three requirements

• The objectives should be achieved early enough to allow ecosystem to adapt naturally to changing climate

• Food production should not be threatened

• Effort to minimize greenhouse gases (GHG) and climate change should be consistent with sustainable economic growth.

Major Issues Discussed

• Emission Reduction

• Emission trading

• Joint implementation

Six GHG• The targets cover emissions of the six

main greenhouse gases, namely:

– Carbon dioxide (CO2);– Methane (CH4);– Nitrous oxide (N2O);– Hydrofluorocarbons (HFCs);– Perfluorocarbons (PFCs); and– Sulphur hexafluoride (SF6)