Population and the environment - Global population futures Flashcards
what is the ozone layer and how is it depleting
recent phenomenon
cause by halogenated chemicals e.g. chlorofluorocarbons used in fridges, insulations and spray can propellants
Chemicals react with and destroy the ozone molecule in the extreme cold of the polar stratosphere
Destruction of ozone occurs mainly in late winter/early spring
Stratospheric ozone layer utilises and filters out incoming solar radiation
If ozone becomes depleted more UV rays will reach earth which cause serious impacts on human, flora and fauna
Extended exposure to UV rays has harmful impacts on human health - increases prevalence of skin cancers, cataract formation, increase in other eyes diseases and an increase in infectious diseases due to excessive UV radiation weakening the human immune system
what are the risks of skin cancer
skin cancers are caused by exposure to sun
long term exposure or short periods of intense sun exposure and burning
UV light in sunlight damages the DNA in skin cells
Malignant melanoma incidence rates have increased more than fivefold since mid 1970s
Melanomas more likely to affect older people and those from more affluent areas
Office for National Statistics - rates of newly diagnosed malignant melanoma skin cancer highest in South West and South East England
Australia has highest rate of skin cancer in world
Combination of the predominantly light skinned population, tropical latitudes with high levels of UV radiation and cultural emphasis on outdoor activities contributed
Two out of three australians have skin cancer by the age of 70
Around 2,000 australians die from skin cancer each year
Skin cancers account for about 80% of all new cancer diagnosed each year in australia each year australians are 4x more likely to develop a common skin cancer than any other form of cancer
calculated that skin cancer costs health system AU$512.3 million in 2010 (diagnoses, treatment and pathology)
What are the risks of cataracts
eye damage causes a loss of transparency in the lens of the eye leading to cloudiness of vision, can eventually result in blindness
Different types
number of factors can lead to formation including being a natural part ageing process, a result of diabetes, Smoke from burning fuel wood and cigarettes, poor nutrition, Exposure to UV radiation damage different parts of the eye including the lense and research shows it appears to be a major risk factor for cataract development
leading causes of blindness in the world
Proteins in eye unravel, tangle and accumulate pigments that cloud the lens and eventually lead to blindness
Increased ozone depletion means anyone who spends a lot of their time outdoors is at risk of eye problems from UV radiation but extent of risk depends on a number of factors -
Geographic location - UV levels greater in tropical areas near equator
Altitude - UV levels greater at high altitude
Time of day - UV levels greater in wide open spaces, especially when highly reflective surfaces are present like snow and sand, exposure is less likely in urban settings where tall buildings shade by the streets
UV levels not significantly affected by cloud cover and risk of UV exposure can be quite high even on hazy or overcast days
because UV is invisible radiation not visible
Wearing good quality sunglasses block harmful UV radiation and close fitting wrap around styles are better as they prevent sunlight entering the peripheries of the glasses
Only effective treatment of cataracts is surgery to remove the cloudy lens and replace it with clear plastic intraocular lens implant
Cataracts severely diminishes the eyesight of millions of people in both the developing and developed world
those living in rural areas in developing countries are disproportionately affected by UV induced cataracts and they are less able to afford prevention or treatment for the problem
Sustained 10% depletion of the ozone layer is expected to result in nearly 2 million new cases of cataracts globally
What are the health impacts of climate change
climate change has three kinds health impacts
Relatively direct impacts - caused by increases in the frequency or severity of extreme weather events such as
Storms - increase the risk of dangerous flooding, high winds and other threats
Warmer average temperature - hotter days and more frequent and longer heatwaves
Consequences of environmental change and ecological disruption that occur
Increased concentrations of unhealthy air and water pollutants
Changes in temp and precipitation patterns could exacerbate the spread of some vector borne diseases
Consequences associated with demoralised populations in the wake of climate induced economic dislocation, environmental decline and conflict situations
Greater frequency of infectious disease epidemics following floods and storms
Substantial traumatic, nutritional or psychological health effects following population displacement from sea level rise or increased storm activity
May bring some localised benefits
Fewer winter deaths in temperate climates
Increased food production in certain areas
WHO suggests health effects of changing climate are negative
Between 2030 and 2050 WHO estimate 250,000 additional deaths per year from malnutrition, malaria, diarrhoea and heat stress
Certain groups particularly vulnerable for certain impacts
Vulnerability depends on factors
Population density
Level of economic development
Food availability
Income level and distribution
Local environmental conditions
Pre existing health status
Quality and availability of public healthcare
E.g. elderly and poor most at risk of thermal extremes
What are the health impacts of thermal stress
Change in mortality
Research by intergovernmental panel on climate change
climate change cause increased heat related mortality and morbidity
decreased clot related mortality in temperate countries
Change in temp at both extremes affects both cardiovascular and respiratory mortality
what are the health impacts of heatwaves
Main risks
Dehydration
Overheating
Heat exhaustion
Heat stroke
Groups particularly at risk when weather is very hot
Very young
Elderly
Seriously ill
Northern and western europe experiencing more frequent heatwaves
August 2003 France and Spain unprecedented high temps lasted for 3 weeks
15,00 excess deaths
Who reported 70,000 excess deaths across whole europe during same period
900 excess deaths were caused by summer heatwaves in UK in 2019
320 in 6 day heatwave in late august
Elderly disproportionately affected
Heatwaves lead directly or indirectly to other health risks
Photochemical smogs caused by UV light reacting with nitrogen dioxide in the atmosphere to form ground level ozone, nitric acids and other pollutants these can cause eye irritation and respiratory problems
The growth of blue-green algae in water courses - can cause problems for aquatic life including fish as well as toxic algal blooms causing problems for public health recreational water activities
Health and environmental problems including odour, dust and vermin infestation measures may be necessary to mitigate infestation including more frequent waste collections and extra pollution controls at landfills and other waste treatment facilities
Wildfires
Water shortages
Heatwaves much bigger health impacts in cities that in surrounding suburban and rural areas
Impact in mortality from heat stress more significant in developing countries (mexico city, New Delhi) where populations especially vulnerable as they lack the resources to deal with heatwaves
What are the health impacts of cold spells
Many temperate countries clear seasonal variation in mortality
Death rates in winter 25% higher than summer
Extremes of cold impact severely on those suffering with both cardiovascular and respiratory diseases and lead to an increase in mortality
Over 34% of excess winter deaths in UK caused by respiratory diseases in 2017-18
Annual outbreaks of winter diseases such as influenza which have large influence in winter mortality are not strongly associated with colder temperatures
Climate change likely to bring milder winters in temperate regions
Research indicates most cities global climate change likely to lead to reduction in mortality rates due to decreasing winter mortality
Effect most pronounced for cardiovascular mortality in elderly people in cities which experience temperature or cold climate
conflicting evidence to whether the decreases in winter mortality are greater or less than increase in summer deaths due to heatwaves
Severe cold thought to have larger impact on morality than extreme heat
other factors affecting winter mortality suggest that negative impacts of more frequent heat waves outweigh benefits of fewer colder days
Net impact in mortality is likely to vary between populations
What are the health impacts of Emergence and changing distribution of vector borne diseases
Important determinants of vector borne disease transmission
Vector survival and reproduction
Vectors biting rate
Pathogens incubation rate within the vector organism
Vectors pathogens and host each survive and reproduce within a range of optimal climatic conditions
Temperature and precipitation most important
Altitude wind and daylight duration also important
Changes in temp and rainfall regimes resulting from global climate change will alter geographic distribution of optimal conditions for most vectors
Ranges of vector borne diseases are expanding
Spurred by anthropogenic factors
By 2100 estimated that average global temp risen by 1.5-5.0
Increases likelihood of many vector borne diseases in new ares
Greatest effect of transmissions likely in extremes of range of temps at which transmission occurs
Diseases lie in 14-18 degrees celsius and the lower end at 35-40 degrees at upper end
what are the health impacts of malaria and dengue
Most important vector borne diseases in tropics and subtropics
Populations living at the present margins of malaria and dengue without affecting primary health care will be the most susceptible if these diseases expand their geographic range in a warmer world
Adede mosquito vector of dengue is sensitive to climatic conditions and studies suggest that climate change could expose an additional one billion people to transmissions by the end of the century
Malaria likely to spread by 2050 based on hadley center climate chane models high scenario
Areas where climate will be conducive to malaria in 2050
North east coast of America
Turkey
East china
Other areas may become free of malaria as climate changes
Climatic anomalies associated with the EL Nino Southern Oscillation phenomenon resulting in drought and floods are also expected to increase in frequency and intensity and have been linked to outbreaks of malaria in Africa asia and south america
what are the health impacts of lyme disease
Most common vector borne disease in temperate climates of the northern hemisphere including the USA and Europe
Borrelia bacteria is transmitted to humans by the bite if infected deer ticks
An emerging vector borne disease thought to be associated with warmer and more humid conditions
what are the health impacts of west nile virus
Emergent disease transmitted by Culex species of mosquito which can have different climatic tolerance range and can survive in more temperate regions
Human infections attributable to WNV have been reported in many countries in the world for over 50 years
Since 1997 it has spread widely and in 1999 the virus reached New York resulting in a large and dramatic outbreak that spread throughout the USA in the following years
Since its introduction in the USA the virus has spread and is now widely established from canada to venezuela
The WNV outbreak in the USA (1990-2010) highlighted the fact that establishment of vector borne pathogens outside their current habitat present a serious danger to the world
What are the health impacts of zika virus
Infection caused by bite of infectes aedes mosquito
Causes
Rash
Mild fever
Conjunctivitis
Muscle pain
Virus isolated in 1947 in the zika forest in uganda
Remained mainly in africa with sporratic outbreaks in asia until 2014
Chile notified WHO of virus on easter island
2015 spread into south and central america and the caribbean
Preaking in americas in 2016 it has since declined there
2019 WHO reported 87 countries with evidence of mosquito bourne transmissions
Countries located in africa the americas, south east asia and the wester pacific
What are the direct health impacts of agriculture productivity
Direct impacts
Higher growing season temperatures will significantly affect agricultural yield, farm income and food security
Will be gains and losses depending on the location of the gowing season
Gains
In mid and high altitudes the crop yield are projected to increase and extend northwards especially for cereals and cool season seed crops such as oil
Crops grown in lower altitudes such as maize sunflower and soya beans could become available further north and at higher altitudes yields could increase by as much as 30% by 2050
Potentially large gains for regions such as russia due to longer planting seasons and more favourable growing conditions amounting to 64% increase over 245 million hectares by the 2080, concerns that gains will be tempered by increase in drought conditions rendering extensive irrigation programmes necessary to benefit from the warmer temperatures
Without adaptations by farmers climate change may not necessarily benefit productivity
Increase in the mean growing season temperature will bring forward harvest time of current varieties and possibly reduce final yield without adaptation to a longer growing season
Losses in productivity
Areas where temps are already close to psychological limits for crops e.g. seasonally arid regions, higher temps will be detrimental, increasing heat stress on crops and water loss by evaporation. Significant modifications to crops strains and/or farming methods may be necessary if agricultural production is to be feasible in such conditions
Varying rainfall patterns will have significant impact on productivity, impact of climate change on regional precipitation is difficult to forecast but there is confidence in projections of a general increase in high altitude rainfall, especially in winter and overall decrease in parts of tropics and subtropics
Indirect impacts
Climate change also impact indirectly and adversely on crops through effects such as
Pests and diseases
Pests such as aphids respond positively to higher levels of co2
Increased temps also reduce their overwintering mortality enabling earlier and more widespread dispersion
Changes in water availability owing to distant climate changes
Water for irrigation often extracted from rivers which depend on distant climatic conditions
Agriculture along the nile in egypt depends on rainfall in the upper reaches of the river in the ethiopian highlands or rwanda mountians
Sea level rise
Vulnerability of crop productivity is greatest where a large sea level rise occurs in conjunction with low lying coastal agriculture
May result in saltwater incursions into aquifers used for irrigation and soils salinisation during fertile farmland near to river deltas
what are the indirect health impacts on agriculture productivity
Indirect impacts
Climate change also impact indirectly and adversely on crops through effects such as
Pests and diseases
Pests such as aphids respond positively to higher levels of co2
Increased temps also reduce their overwintering mortality enabling earlier and more widespread dispersion
Changes in water availability owing to distant climate changes
Water for irrigation often extracted from rivers which depend on distant climatic conditions
Agriculture along the nile in egypt depends on rainfall in the upper reaches of the river in the ethiopian highlands or rwanda mountians
Sea level rise
Vulnerability of crop productivity is greatest where a large sea level rise occurs in conjunction with low lying coastal agriculture
May result in saltwater incursions into aquifers used for irrigation and soils salinisation during fertile farmland near to river deltas
what affects do climate change have on nutritional standards
Impact if climate change on global food production will have uncertain and varying consequences for human health and nutrition
Can be viewed from different perspectives depending on levels of development
