Scientists learn about the past climate conditions from such things as tree ring analysis, fossil evidence, and analysis of patterns and chemical composition in coral skeletons and ice cores.
While there are many substances that act as greenhouse gases, two of the most important are water and carbon dioxide, or CO2.
Transcript of "Global climate change"
Global Climate Change: Health Risks and Preventive Strategies By Dr Nik Nor Ronaidi bin Nik Mahdi
Content1. Summary of global climate change2. Possible risks to human health3. What are the main risks to human health / health impact?4. Action taken previously and currently to prevent / mitigate the health risks / health impact5. Possible actions to prevent /lessen the health impact related to global climate change6. Roles for doctors and other health professionals to reduce health risk
Weather and ClimateWhat is weather?•Weather is the state of atmospheric conditions (i.e., hot/cold, wet/dry,calm/stormy, sunny/cloudy) that exist over relatively short periods of time(hours to a couple of days).•Weather includes the passing of a thunderstorm, hurricane, or blizzard, andthe persistence of a heat wave, or a cold snap.What is Climate?•Climate is the weather we expect over the period of a month, a season, adecade, or a century.•More technically, climate is defined as the weather conditions resulting fromthe mean state of the atmosphere-ocean-land system, often described in termsof "climate normals" or average weather conditions.
Climate Change is…• Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). – When due to natural processes, it is usually referred to as global climate variability – Usually refers to changes forced by human activities that change the atmosphere
Global warming is…• …the increase in the average surface air temperature of the planet that is a result of the buildup of heat-trapping or "greenhouse" gases in the atmosphere.
Climate Change or Global Warming?• The term CLIMATE CHANGE is often used interchangeably with GLOBAL WARMING.• The phrase climate change‘ is growing in preferred use to global warming because it convey there are other changes in addition to rising temperatures.” (National Academy of Sciences)
Climate Change Is Happening Now.• Warming of the global climate is clear and is shown by – increases in global average air and ocean temperatures, – widespread melting of snow and ice – rising global average sea level – the 10 warmest years on record have all occurred since 1990.
How do we know?Scientists learn about the past climate conditions from such things as tree ringanalysis, fossil evidence, and analysis of patterns and chemical composition incoral skeletons and ice cores.
What causes Earth’s climate to change?Natural causes:• Variations in the Earths orbital characteristics.• Atmospheric carbon dioxide variations.• Volcanic eruptions• Variations in solar output.Anthropogenic: Human activities – any activity that releases “greenhouse gases” into the atmosphere
The Greenhouse Effect• The Earth receives ultraviolet (UV) radiation from the sun, absorbs it, and then radiates the energy out as infrared radiation• The Earth is warmer because our atmosphere traps some of the outgoing IR radiation. This is a natural process known as the greenhouse effect.• The greenhouse effect is a good thing, without it the Earth would become too cold for life to exist.• However, man’s activities appear to be altering the natural balance.
Greenhouse Gasses• Greenhouse gases are atmospheric gases that trap infrared radiation emitted from the earth.• Most of the significant greenhouse gases are long-lived and well- mixed: • Long-lived means they are chemically stable and therefore last years in the atmosphere • Well-mixed means they are evenly distributed in the atmosphere. • This family includes carbon dioxide, methane, oxides of nitrogen, and halocarbons.• Water vapor is a greenhouse gas that is neither well-mixed nor long-lived. Because of this, its overall effect on global warming is the least understood.
Greenhouse gases Carbon dioxideNitrous oxide Methane Water Sulfur hexafluoride
Modulating Health effects Health Effects influences Temperature-related Temperature -related illness and death Extreme weather- Extreme(floods, - related weather storms, related health effects etc.) health effects Human Air pollution-related Air pollution-related exposures health effects Regional weather Microbial changes: Contamination Water and food-borne Water and food-borneClimate changes pathways Contamination paths diseasesChange • eat waves H Transmission dynamics Transmission Vectorborne and - Extreme weather • dynamics rodentborne diseases borne diseases rodent- • emperature T • Precipitation Changes in agro- Effects of food and •Sea-level ecosystems, hydrology water shortages rise Socioeconomic and Mental, nutritional, demographic disruption infectious-disease and other effects