Water resources, agriculture, forestry and society and human health 

Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial, household, recreational and environmental activities. The majority of human uses require fresh water.

97 percent of the water on the Earth is salt water and only three percent is fresh water; slightly over two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air.

Fresh water is a renewable resource, yet the world's supply of ground water is steadily decreasing, with depletion occurring most prominently in Asia and North America, although it is still unclear how much natural renewal balances this usage, and whether ecosystems are threatened. The framework for allocating water resources to water users (where such a framework exists) is known as water rights.

Climate change

Climate change could have significant impacts on water resources around the world because of the close connections between the climate and hydrological cycle. Rising temperatures will increase evaporation and lead to increases in precipitation, though there will be regional variations in rainfall. Overall, the global supply of freshwater will increase. Both droughts and floods may become more frequent in different regions at different times, and dramatic changes in snowfall and snow melt are expected in mountainous areas. Higher temperatures will also affect water quality in ways that are not well understood. Possible impacts include increased eutrophication. Climate change could also mean an increase in demand for farm irrigation, garden sprinklers, and perhaps even swimming pools. There is now ample evidence that increased hydrologic variability and change in climate has and will continue have a profound impact on the water sector through the hydrologic cycle, water availability, water demand, and water allocation at the global, regional, basin, and local levels.

Agriculture

Climate change and agriculture are interrelated processes, both of which take place on a global scale. Global warming is projected to have significant impacts on conditions affecting agriculture, including temperature, carbon dioxide, glacial run-off, precipitation and the interaction of these elements. These conditions determine the carrying capacity of the biosphere to produce enough food for the human population and domesticated animals. The overall effect of climate change on agriculture will depend on the balance of these effects. Assessment of the effects of global climate changes on agriculture might help to properly anticipate and adapt farming to maximize agricultural production.

At the same time, agriculture has been shown to produce significant effects on climate change, primarily through the production and release of greenhouse gases such as carbon dioxide, methane, and nitrous oxide, but also by altering the Earth's land cover, which can change its ability to absorb or reflect heat and light, thus contributing to radiative forcing. Land use change such as deforestation and desertification, together with use of fossil fuels, are the major anthropogenic sources of carbon dioxide; agriculture itself is the major contributor to increasing methane and nitrous oxide concentrations in Earth's atmosphere.

Impact of climate change on agriculture

Despite technological advances, such as improved varieties, genetically modified organisms, and irrigation systems, weather is still a key factor in agricultural productivity, as well as soil properties and natural communities. The effect of climate on agriculture is related to variabilities in local climates rather than in global climate patterns. The Earth's average surface temperature has increased by 1.5°F (0.83°C) since 1880. Consequently, agronomists consider any assessment has to be individually consider each local area.

On the other hand, agricultural trade has grown in recent years, and now provides significant amounts of food, on a national level to major importing countries, as well as comfortable income to exporting ones. The international aspect of trade and security in terms of food implies the need to also consider the effects of climate change on a global scale.

A study published in Science suggests that, due to climate change, "southern Africa could lose more than 30% of its main crop, maize, by 2030. In South Asia losses of many regional staples, such as rice, millet and maize could top 10%".

The Intergovernmental Panel on Climate Change (IPCC) has produced several reports that have assessed the scientific literature on climate change. The IPCC Third Assessment Report, published in 2001, concluded that the poorest countries would be hardest hit, with reductions in crop yields in most tropical and sub-tropical regions due to decreased water availability, and new or changed insect pest incidence. In Africa and Latin America many rainfed crops are near their maximum temperature tolerance, so that yields are likely to fall sharply for even small climate changes; falls in agricultural productivity of up to 30% over the 21st century are projected. Marine life and the fishing industry will also be severely affected in some places.

Climate change induced by increasing greenhouse gases is likely to affect crops differently from region to region. For example, average crop yield is expected to drop down to 50% in Pakistan according to the UKMO scenario whereas corn production in Europe is expected to grow up to 25% in optimum hydrologic conditions.

More favourable effects on yield tend to depend to a large extent on realization of the potentially beneficial effects of carbon dioxide on crop growth and increase of efficiency in water use. Decrease in potential yields is likely to be caused by shortening of the growing period, decrease in water availability and poor vernalization.

In the long run, the climatic change could affect agriculture in several ways :

·         productivity, in terms of quantity and quality of crops

·         agricultural practices, through changes of water use (irrigation) and agricultural inputs such as herbicides, insecticides and fertilizers

·         environmental effects, in particular in relation of frequency and intensity of soil drainage (leading to nitrogen leaching), soil erosion, reduction of crop diversity

·         rural space, through the loss and gain of cultivated lands, land speculation, land renunciation, and hydraulic amenities.

·         adaptation, organisms may become more or less competitive, as well as humans may develop urgency to develop more competitive organisms, such as flood resistant or salt resistant varieties of rice.

They are large uncertainties to uncover, particularly because there is lack of information on many specific local regions, and include the uncertainties on magnitude of climate change, the effects of technological changes on productivity, global food demands, and the numerous possibilities of adaptation.

Most agronomists believe that agricultural production will be mostly affected by the severity and pace of climate change, not so much by gradual trends in climate. If change is gradual, there may be enough time for biota adjustment. Rapid climate change, however, could harm agriculture in many countries, especially those that are already suffering from rather poor soil and climate conditions, because there is less time for optimum natural selection and adaption.

But much remains unknown about exactly how climate change may affect farming and food security, in part because the role of farmer behaviour is poorly captured by crop-climate models. For instance, Evan Fraser, a geographer at the University of Guelph in Ontario Canada, has conducted a number of studies that show that the socio-economic context of farming may play a huge role in determining whether a drought has a major, or an insignificant impact on crop production. In some cases, it seems that even minor droughts have big impacts on food security (such as what happened in Ethiopia in the early 1980s where a minor drought triggered a massive famine), versus cases where even relatively large weather related problems were adapted to without much hardship. Evan Fraser combines socio-economic models along with climatic models to identify “vulnerability hotspots”^[8] One such study has identified US maize (corn) production as particularly vulnerable to climate change because it is expected to be exposed to worse droughts, but it does not have the socio-economic conditions that suggest farmers will adapt to these changing conditions.

Observed impacts

So far, the effects of regional climate change on agriculture have been relatively limited. Changes in crop phenology provide important evidence of the response to recent regional climate change. Phenology is the study of natural phenomena that recur periodically, and how these phenomena relate to climate and seasonal changes. A significant advance in phenology has been observed for agriculture and forestry in large parts of the Northern Hemisphere.

Droughts have been occurring more frequently because of global warming and they are expected to become more frequent and intense in Africa, southern Europe, the Middle East, most of the Americas, Australia, and Southeast Asia. Their impacts are aggravated because of increased water demand, population growth, urban expansion, and environmental protection efforts in many areas. Droughts result in crop failures and the loss of pasture grazing land for livestock.

Their central estimates of changes in crop yields are shown above. Actual changes in yields may be above or below these central estimates. US NRC (2011) also provided an estimated the "likely" range of changes in yields. "Likely" means a greater than 67% chance of being correct, based on expert judgement. The likely ranges are summarized in the image descriptions of the two graphs.

Food security

The IPCC Fourth Assessment Report also describes the impact of climate change on food security. Projections suggested that there could be large decreases in hunger globally by 2080, compared to the (then-current) 2006 level. Reductions in hunger were driven by projected social and economic development. For reference, the Food and Agriculture Organization has estimated that in 2006, the number of people undernourished globally was 820 million. Three scenarios without climate change (SRES A1, B1, B2) projected 100-130 million undernourished by the year 2080, while another scenario without climate change (SRES A2) projected 770 million undernourished. Based on an expert assessment of all of the evidence, these projections were thought to have about a 5-in-10 chance of being correct.

The same set of greenhouse gas and socio-economic scenarios were also used in projections that included the effects of climate change. Including climate change, three scenarios (SRES A1, B1, B2) projected 100-380 million undernourished by the year 2080, while another scenario with climate change (SRES A2) projected 740-1,300 million undernourished. These projections were thought to have between a 2-in-10 and 5-in-10 chance of being correct.

Projections also suggested regional changes in the global distribution of hunger. By 2080, sub-Saharan Africa may overtake Asia as the world's most food-insecure region. This is mainly due to projected social and economic changes, rather than climate change.

"Climate change merely increases the urgency of reforming trade policies to ensure that global food security needs are met" said C. Bellmann, ICTSD Programmes Director. A 2009 ICTSD-IPC study by Jodie Keane suggests that climate change could cause farm output in sub-Saharan Africa to decrease by 12 percent by 2080 - although in some African countries this figure could be as much as 60 percent, with agricultural exports declining by up to one fifth in others. Adapting to climate change could cost the agriculture sector $14bn globally a year, the study finds.

Poverty impacts

Researchers at the Overseas Development Institute (ODI) have investigated the potential impacts climate change could have on agriculture, and how this would affect attempts at alleviating poverty in the developing world. They argued that the effects from moderate climate change are likely to be mixed for developing countries. However, the vulnerability of the poor in developing countries to short term impacts from climate change, notably the increased frequency and severity of adverse weather events is likely to have a negative impact. This, they say, should be taken into account when defining agricultural policy.

 

 

Crop development models

Because these models are necessarily simplifying natural conditions (often based on the assumption that weeds, disease and insect pests are controlled), it is not clear whether the results they give will have an in-field reality. However, some results are partly validated with an increasing number of experimental results.

Other models, such as insect and disease development models based on climate projections are also used (for example simulation of aphid reproduction or septoria (cereal fungal disease) development).

Scenarios are used in order to estimate climate changes effects on crop development and yield. Each scenario is defined as a set of meteorological variables, based on generally accepted projections. For example, many models are running simulations based on doubled carbon dioxide projections, temperatures raise ranging from 1 °C up to 5 °C, and with rainfall levels an increase or decrease of 20%. Other parameters may include humidity, wind, and solar activity. Scenarios of crop models are testing farm-level adaptation, such as sowing date shift, climate adapted species (vernalisation need, heat and cold resistance), irrigation and fertilizer adaptation, resistance to disease. Most developed models are about wheat, maize, rice and soybean.

Temperature potential effect on growing period

Duration of crop growth cycles are above all, related to temperature. An increase in temperature will speed up development. In the case of an annual crop, the duration between sowing and harvesting will shorten (for example, the duration in order to harvest corn could shorten between one and four weeks). The shortening of such a cycle could have an adverse effect on productivity because senescence would occur sooner.

 

Effect of elevated carbon dioxide on crops

Carbon dioxide is essential to plant growth. Rising CO₂ concentration in the atmosphere can have both positive and negative consequences.

Increased CO₂ is expected to have positive physiological effects by increasing the rate of photosynthesis. Currently, the amount of carbon dioxide in the atmosphere is 380 parts per million. In comparison, the amount of oxygen is 210,000 ppm. This means that often plants may be starved of carbon dioxide as the enzyme that fixes CO₂, rubisco, also fixes oxygen in the process of photorespiration. The effects of an increase in carbon dioxide would be higher on C3 crops (such as wheat) than on C4 crops (such as maize), because the former is more susceptible to carbon dioxide shortage. Studies have shown that increased CO₂ leads to fewer stomata developing on plants which lead to reduced water usage. Under optimum conditions of temperature and humidity, the yield increase could reach 36%, if the levels of carbon dioxide are doubled.

Further, few studies have looked at the impact of elevated carbon dioxide concentrations on whole farming systems. Most models study the relationship between CO₂ and productivity in isolation from other factors associated with climate change, such as an increased frequency of extreme weather events, seasonal shifts, and so on.

In 2005, the Royal Society in London concluded that the purported benefits of elevated carbon dioxide concentrations are "likely to be far lower than previously estimated when factors such as increasing ground-level ozone are taken into account."

Effect on quality

According to the IPCC's TAR, "The importance of climate change impacts on grain and forage quality emerges from new research. For rice, the amylose content of the grain—a major determinant of cooking quality—is increased under elevated CO₂" . Cooked rice grain from plants grown in high-CO₂ environments would be firmer than that from today's plants. However, concentrations of iron and zinc, which are important for human nutrition, would be lower. Moreover, the protein content of the grain decreases under combined increases of temperature and CO₂  Studies using FACE have shown that increases in CO₂ lead to decreased concentrations of micronutrients in crop plants. This may have knock-on effects on other parts of ecosystems as herbivores will need to eat more food to gain the same amount of protein.

Studies have shown that higher CO₂ levels lead to reduced plant uptake of nitrogen (and a smaller number showing the same for trace elements such as zinc) resulting in crops with lower nutritional value. This would primarily impact on populations in poorer countries less able to compensate by eating more food, more varied diets, or possibly taking supplements.

Reduced nitrogen content in grazing plants has also been shown to reduce animal productivity in sheep, which depend on microbes in their gut to digest plants, which in turn depend on nitrogen intake.

Agricultural surfaces and climate changes

Climate change may increase the amount of arable land in high-latitude region by reduction of the amount of frozen lands. A 2005 study reports that temperature in Siberia has increased three degree Celsius in average since 1960 (much more than the rest of the world). However, reports about the impact of global warming on Russian agriculture indicate conflicting probable effects : while they expect a northward extension of farmable lands, they also warn of possible productivity losses and increased risk of drought.

Sea levels are expected to get up to one meter higher by 2100, though this projection is disputed. A rise in the sea level would result in an agricultural land loss, in particular in areas such as South East Asia. Erosion, submergence of shorelines, salinity of the water table due to the increased sea levels, could mainly affect agriculture through inundation of low-lying lands.

Low lying areas such as Bangladesh, India and Vietnam will experience major loss of rice crop if sea levels rise as expected by the end of the century. Vietnam for example relies heavily on its southern tip, where the Mekong Delta lies, for rice planting. Any rise in sea level of no more than a meter will drown several km² of rice paddies, rendering Vietnam incapable of producing its main staple and export of rice.

Erosion and fertility

The warmer atmospheric temperatures observed over the past decades are expected to lead to a more vigorous hydrological cycle, including more extreme rainfall events. Erosion and soil degradation is more likely to occur. Soil fertility would also be affected by global warming. However, because the ratio of carbon to nitrogen is a constant, a doubling of carbon is likely to imply a higher storage of nitrogen in soils as nitrates, thus providing higher fertilizing elements for plants, providing better yields. The average needs for nitrogen could decrease, and give the opportunity of changing often costly fertilisation strategies.

Due to the extremes of climate that would result, the increase in precipitations would probably result in greater risks of erosion, whilst at the same time providing soil with better hydration, according to the intensity of the rain. The possible evolution of the organic matter in the soil is a highly contested issue: while the increase in the temperature would induce a greater rate in the production of minerals, lessening the soil organic matter content, the atmospheric CO₂ concentration would tend to increase it.

Potential effects of global climate change on pests, diseases and weeds

A very important point to consider is that weeds would undergo the same acceleration of cycle as cultivated crops, and would also benefit from carbonaceous fertilization. Since most weeds are C3 plants, they are likely to compete even more than now against C4 crops such as corn. However, on the other hand, some results make it possible to think that weed killers could gain in effectiveness with the temperature increase.

Global warming would cause an increase in rainfall in some areas, which would lead to an increase of atmospheric humidity and the duration of the wet seasons. Combined with higher temperatures, these could favor the development of fungal diseases. Similarly, because of higher temperatures and humidity, there could be an increased pressure from insects and disease vectors.

Glacier retreat and disappearance

The continued retreat of glaciers will have a number of different quantitative impacts. In areas that are heavily dependent on water runoff from glaciers that melt during the warmer summer months, a continuation of the current retreat will eventually deplete the glacial ice and substantially reduce or eliminate runoff. A reduction in runoff will affect the ability toirrigate crops and will reduce summer stream flows necessary to keep dams and reservoirs replenished.

Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers. India, China, Pakistan, Afghanistan, Bangladesh, Nepal and Myanmar could experience floods followed by severe droughts in coming decades. In India alone, the Ganges provides water for drinking and farming for more than 500 million people. The west coast of North America, which gets much of its water from glaciers in mountain ranges such as the Rocky Mountains and Sierra Nevada, also would be affected.

Ozone and UV-B

Some scientists think agriculture could be affected by any decrease in stratospheric ozone, which could increase biologically dangerous ultraviolet radiation B. Excess ultraviolet radiation B can directly affect plant physiology and cause massive amounts of mutations, and indirectly through changed pollinator behavior, though such changes are not simple to quantify. However, it has not yet been ascertained whether an increase in greenhouse gases would decrease stratospheric ozone levels.

In addition, a possible effect of rising temperatures is significantly higher levels of ground-level ozone, which would substantially lower yields.

ENSO effects on agriculture

ENSO (El Niño Southern Oscillation) will affect monsoon patterns more intensely in the future as climate change warms up the ocean's water. Crops that lie on the equatorial belt or under the tropical Walker circulation, such as rice, will be affected by varying monsoon patterns and more unpredictable weather. Scheduled planting and harvesting based on weather patterns will become less effective.

Areas such as Indonesia where the main crop consists of rice will be more vulnerable to the increased intensity of ENSO effects in the future of climate change. University of Washington professor, David Battisti, researched the effects of future ENSO patterns on the Indonesian rice agriculture using [IPCC]'s 2007 annual report and 20 different logistical models mapping out climate factors such as wind pressure, sea-level, and humidity, and found that rice harvest will experience a decrease in yield. Bali and Java, which holds 55% of the rice yields in Indonesia, will be likely to experience 9–10% probably of delayed monsoon patterns, which prolongs the hungry season. Normal planting of rice crops begin in October and harevest by January. However, as climate change affects ENSO and consequently delays planting, harvesting will be late and in drier conditions, resulting in less potential yields.

Impact of agriculture on climate change

The agricultural sector is a driving force in the gas emissions and land use effects thought to cause climate change. In addition to being a significant user of land and consumer of fossil fuel, agriculture contributes directly to greenhouse gas emissions through practices such as rice production and the raising of livestock; according to the Intergovernmental Panel on Climate Change, the three main causes of the increase in greenhouse gases observed over the past 250 years have been fossil fuels, land use, and agriculture.

Land use

Agriculture contributes to greenhouse gas increases through land use in four main ways:

·         CO₂ releases linked to deforestation

·         Methane releases from rice cultivation

·         Methane releases from enteric fermentation in cattle

·         Nitrous oxide releases from fertilizer application

Together, these agricultural processes comprise 54% of methane emissions, roughly 80% of nitrous oxide emissions, and virtually all carbon dioxide emissions tied to land use.^[1]

The planet's major changes to land cover since 1750 have resulted from deforestation in temperate regions: when forests and woodlands are cleared to make room for fields and pastures, the albedo of the affected area increases, which can result in either warming or cooling effects, depending on local conditions. Deforestation also affects regional carbon reuptake, which can result in increased concentrations of CO₂, the dominant greenhouse gas. Land-clearing methods such as slash and burn compound these effects by burning biomatter, which directly releases greenhouse gases and particulate matter such as soot into the air.

Livestock

Livestock and livestock-related activities such as deforestation and increasingly fuel-intensive farming practices are responsible for over 18% of human-made greenhouse gas emissions, including:

·         9% of global carbon dioxide emissions

·         35–40% of global methane emissions (chiefly due to enteric fermentation and manure)

·         64% of global nitrous oxide emissions (chiefly due to fertilizer use.)

Livestock activities also contribute disproportionately to land-use effects, since crops such as corn and alfalfa are cultivated in order to feed the animals.

Worldwide, livestock production occupies 70% of all land used for agriculture, or 30% of the land surface of the Earth.

·         Aridification

·         Biochar

·         Desertification

·         Drought

·         Environmental issues with agriculture

·         Fisheries and Climate Change

·         Food security

·         Global warming and wine

·         International Assessment of Agricultural Science and Technology for Development addressing the links between climate change & agriculture

·         Land Allocation Decision Support System – a research tool that is used to test how climate change may affect agriculture (e.g. yield and quality)

·         Retreat of glaciers since 1850

·         Slash-and-char

·         Terra preta

·         Water crisis

Effects of global warming on human health

From Wikipedia, the free encyclopedia

The effects of global warming include effects on human health. This article describes some of those effects on individuals and populations. The observed and projected increased frequency and severity of climate related impacts will further exacerbate the effects on human health.

Contents

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Impact on infectious diseases[edit]

Warming oceans and a changing climate are resulting in extreme weather patterns which have brought about an increase ofinfectious diseases—both new and re-emerging.^[1][2] These extreme weather patterns are creating extended rainy seasonsin some areas,^[3] and extended periods of drought in others,^[4] as well as introducing new climates to different regions.^[4]These extended seasons are creating climates that are able to sustain vectors for longer periods of time, allowing them to multiply rapidly, and also creating climates that are allowing the introduction and survival of new vectors.^[1]

Impact of extreme weather[edit]

“The rise of extreme weather is itself a symptom of an unstable climate. Moreover, the variance around the long-term warming trend has begun to influence biological systems, Indeed, two main effects of climate change—warming and greater weather variability-mean that millions of people worldwide face a higher risk of infectious disease”.^[3] El Nino is an extreme weather pattern that is often responsible for increased precipitation, resulting in increased flooding, creating a more promising breeding ground for a plethora of vectors that both carry and cause infectious diseases.^[5]

Another result of the warming oceans are stronger hurricanes, which will wreck more havoc on land, and in the oceans,^[5]and create more opportunities for vectors to breed and infectious diseases to flourish.^[1][3] Extreme weather also means stronger winds. These winds can carry vectors tens of thousands of kilometers, resulting in an introduction of new infectious disease to regions that have never seen them before, making the humans in these regions even more susceptible.^[1]

Impact of warmer and wetter climates[edit]

Mosquito-borne diseases are probably the greatest threat to humans as they include malaria, elephantiasis, Rift Valley fever, yellow fever, and dengue fever.^[6][7][8] Studies are showing higher prevalence of these diseases in areas that have experienced extreme flooding and drought.^[6][7] Flooding creates more standing water for mosquitoes to breed; as well, shown that these vectors are able to feed more and grow faster in warmer climates.^[1] As the climate warms over the oceans and coastal regions, warmer temperatures are also creeping up to higher elevations allowing mosquitoes to survive in areas they had never been able to before.^[1] As the climate continues to warm there is a risk that malaria will make a return to the developed world.^[1]

Ticks are also thriving in the warmer temperatures allowing them to feed and grow at a faster rate.^[9] The black legged tick, a carrier of Lyme disease, when not feeding, spends its time burrowed in soil absorbing moisture.^[3][10] Ticks die when the climate either becomes too cold or when the climate becomes too dry, causing the ticks to dry out.^[3][10] The natural environmental controls that used to keep the tick populations in check are disappearing, and warmer and wetter climates are allowing the ticks to breed and grow at an alarming rate, resulting in an increase in Lyme disease, both in existing areas and in areas where it has not been seen before.^[3][9]

Other diseases on the rise due to extreme weather include: hantavirus,^[11] schistosomiasis,^[7][8] onchocerciasis (river blindness),^[8] and tuberculosis.^[2]

Impact of warmer oceans[edit]

The warming oceans are becoming a breeding ground for toxic algae blooms (also known as red tides) and cholera.^[1][8][12]As the nitrogen and phosphorus levels in the oceans increase, the cholera bacteria that lives within zooplankton emerge from their dormant state.^[12] The changing winds and changing ocean currents push the zooplankton toward the coastline, carrying the cholera bacteria, which then contaminate drinking water, causing cholera outbreaks.^[12] As flooding increases there is also in increase in cholera epidemics as the flood waters that are carrying the bacteria are infiltrating the drinking water supply.^[13] El Nino has also been linked with cholera outbreaks because this weather patter warms the shoreline waters, causing the cholera bacteria to multiply rapidly.^[12][13]

Toxic algae blooms (red tides) are the result of a changing and warming climate.^[14] El Nino events precipitation resulting in flooding, which causes the coastal seawater to be infiltrated with runoff from the flooding land resulting in increased nitrogen and phosphorus which feed the algae and spur their growth.^[15] These toxic blooms in turn infect shellfish, which threatens the health of the millions of people who depend on shellfish for protein.^[15] Paralytic shellfish poisoning is the most common result of red tides, as was seen in the 1987 outbreak in Prince Edward Island.^[15] Ciguatera fish poisoning is also a result of red tides.^[16] Humans that ingest these infected reef dwelling fish become ill.^[16] Further, red tides are so powerful that they also cause respiratory illness simply by breathing the air near them.^[15]

Malaria[edit]

Malaria is a mosquito-borne parasitic disease that infects humans and other animals caused by microorganisms in thePlasmodium family. It begins with a bite from an infected female mosquito, which introduces the parasite through its saliva and into the infected host’s circulatory system. It then travels through the bloodstream into the liver where it can mature and reproduce.^[17] The disease causes symptoms that typically include fever, headache, shaking chills, anemia, and in severe cases can progress to coma or death.

Climate is an influential driving force of vector-borne diseases such as malaria. Malaria is especially susceptible to the effects of climate change because mosquitoes lack the mechanisms to regulate their internal temperature. This implies that there is a limited range of climatic conditions within which the pathogen (malaria) and vector (a mosquito) can survive, reproduce and infect hosts.^[18] Vector-borne diseases, such as malaria, have distinctive characteristics that determinepathogenicity. These include: the survival and reproduction rate of the vector, the level of vector activity (i.e. the biting or feeding rate), and the development and reproduction rate of the pathogen within the vector or host.^[18] Changes in climate factors substantially affect reproduction, development, distribution and seasonal transmissions of malaria.

Mosquitoes have a small window for preferential conditions for breeding and maturation. The ultimate breeding and maturing temperature for mosquitoes range from sixteen to eighteen degrees Celsius.^[19] If the temperature is decreased by two degrees, most of the insects will succumb to death. This is why malaria is unsustainable in places with cool winters. If a climate with an average of approximately 16 degrees Celsius experiences an increase of about two degrees, the mature bugs and the larvae flourish.^[1] Female mosquitoes will need more food (human/animal blood) to sustain life and to stimulate production of eggs. This increases the chance of spread of malaria due to more human contact and a higher number of the blood sucking insects surviving and living longer. Mosquitoes are also highly sensitive to changes in precipitation and humidity. Increased precipitation can increase mosquito population indirectly by expanding larval habitat and food supply.^[18]These prime temperatures are creating large breeding grounds for the insects and places for the larvae to mature. Increased temperature is causing snow to melt and stagnant pools of water to become more common.^[1] Bugs that are already carrying the disease are more likely to multiply and infect other mosquitoes causing a dangerous spread of the deadly disease.

Climate change has a direct impact on people’s health in places where Malaria is not prevalent. In communities of higher altitudes in Africa and South America, people are at higher risk for developing malaria in recent years because of an increase temperature. A fluctuation of two or three degrees is creating exceptional breeding grounds for mosquitoes, for larvae to grow and mature mosquitoes carrying the virus to infect people that have never been exposed before.^[1] This is a severe problem because people in these communities have never been exposed to this disease causing an increased risk for complications from malaria such as cerebral malaria (a type of malaria that causes mental disability, paralysis and has a high mortality rate) and death by the disease.^[1] Residents of these communities are being hit hard by malaria because they are unfamiliar with it; they do not know the signs and symptoms and have little to no immunity.

The population at risk of malaria in the absence of climate change is projected to double between 1990 and 2080 to 8820 million, however; unmitigated climate change would, by the 2080s, further increase the population at risk of malaria by another 257 to 323 million.^[20] Therefore, reducing the effects of climate change in the present would reduce the total by about 3.5%, saving tens of thousands of lives worldwide.

If there is a slight discrepancy in the normal temperature, the perfect conditions for the insects to multiply are created. People that have never been infected before are unknowingly at risk for this deadly disease and do not have the immunity to combat it.^[1] An increase in temperature has the potential to cause a widespread epidemic of the disease that has the capacity to wipe out entire populations of people. It is important to track the prevalence, species and number of insects carrying the disease as well as the amount of humans infected in countries and places that have never seen malaria before. It is simple for the slightest of fluctuation in temperature to cause a catastrophic epidemic that has the possibility to end the lives of many innocent and unsuspecting people.^[19]

Dengue Fever[edit]

Background[edit]

Dengue fever is an infectious disease caused by the dengue virus known to be in the tropical regions.^[21] It is transmitted by mosquito Aedes, or A aegypti.^[22]

The cases of Dengue fever increased dramatically since the 1970s and continues to become more prevalent.^[23] This disease is believed to be due to a combination of urbanization, population growth, increased international travel, and global warming.^[24] The same trends also led to the spread of different serotypes of the disease to new areas, and to the emergence of dengue hemorrhagic fever. There are four different types of virues in dengue fever. If someone is infected with one type of dengue virus, he or she will have permanent immunity to that type of dengue virus, but will have short term immunity to the other type of dengue fever.^[21] Some of the symptoms of dengue fever are fever, headache,muscle and joint pains and skin rash.^[25] There is no vaccine for Dengue fever right now and there is no true treatment to get rid of it, but there are treatments to assist with some of the symptoms of dengue, such as the use of oral or intravenous fluids for rehydration.^[25]

Climate Change Impacts[edit]

Dengue fever used to be considered a tropical disease, but climate change is causing dengue fever to spread. Dengue fever is transmitted by certain types of mosquitos, which have been spreading further and further north. This is because some of the climate changes that are occurring are increased heat, precipitation and humidity which create prime breeding grounds for mosquitos.^[26] The hotter and wetter a climate is the faster the mosquitos can mature and the faster the disease can develop. Another influence is the changing El Nino effects that are affecting the climate to change in different areas of the world, causing dengue fever to be able to spread.^[27]

What can be done?[edit]

There are many things that can be done, both on a governmental level and on an individual basis. 1.) Have a better system of detecting when dengue outbreaks may happen. This can be done by monitoring environments, such as temperatures, rainfall and humidity that would be attractive for these types of mosquitos to flourish. 2.) Educating the public: Letting the public know when a dengue outbreak is occurring and what they can do to protect themselves. For example, people should create a living environment that is not attractive to mosquitos (no sitting water), dress in appropriate clothing (light colours, long sleeves)and wear insect repellant.

HIV/AIDS[edit]

Labour Losses Due To HIV AIDS

HIV AIDS and Climate Change are both long wave issues that cause fear and uncertainty in the population. One of the main reasons why climate change appears to have such an impact on HIV/AIDS seems to be related to food shortage. “In the fight against hunger we could now be facing a perfect storm of challenges, including climate change and increasingly severe droughts and floods, soaring food prices and the tightest supplies in recent history, declining levels of food aid, and HIV/AIDS, which also aggravates food insecurity” says Sheeran.^[28] The lack of food security, due to climate change, in South Africa has been affected by HIV/AIDS. In Sub-Saharan Africa over 70% of the population are farmers and human capital has decreased due to HIV/AIDS.^[29] “This reduction in the household labour capabilities severely decreases agricultural output. The source of nourishment and income for the bulk of Sub-Saharan Africa’s population, agricultural output, is further hurt by a loss in the transfer of intergenerational knowledge, as the productive adult population with experience in agricultural labour is the most severely affected by AIDS”.^[29] This has been made worse as 90% of the people infected with HIV/AIDS in sub-Saharan Africa are adults. This not only greatly reduces human capital, but it leaves many children to tend to themselves. Malnutrition, brought about by food security in Sub-Saharan Africa, exacerbates the effects of HIV/AIDS.^[29] A study done in Ethiopia showed that chronic malnutrition was a predictor of first line antiretroviral therapy failure.^[30] This has the potential to create more HIV deaths each year, as immune capabilities are further weakened by Malnutrition. Another important factor about food insecurity is that it could increase the spread of HIV AIDS from the use of Transactional sex. Women who are desperate and suffer malnutrition are more likely to sell their bodies in order to support themselves. Also food insecurity and poverty may prevent people from seeking a diagnosis or prevent them from having the ability to afford treatment.

Secondly the spread of Malaria due to climate change will also be degrading to the burden of disease of HIV/AIDS.^[31] As people become infected by HIV/AIDS and are then exposed to Malaria, it will create an even more substantial loss of life because AIDS victims will be less likely to be able to fight the Malaria infection. Climate change may also increase the spread of HIV/AIDS. As climate change disasters sweep the globe, more people will become displaced, and be forced to live in close quarters to one another. There is evidence to suggest that this could “aggravate gender inequalities"^[31] that have the potential to raise the possibility of transmission of the disease. Migrants often have poor living conditions, are separated from their spouses and families, perform demanding and dangerous jobs and have limited access to health care.^[32] This can all lead to an increased risk of contracting HIV/AIDS.

Lastly climate Change will reduce the funds available to mitigate HIV/AIDS. As more money is spent on repairing infrastructure due the increasing nature of extreme weather, less money will be available for programs to prevent HIV/AIDS and to look after those that are already infected.^[33] This is especially true in underdeveloped countries where they are least able to cope. The governments in these countries are less able to provide for their populations, and will even more under strain from the climate change related costs. This raises the possibility of bankrupt countries that may leed to the Failed state phenomenon. The twin effects of HIV/AIDS and Climate Change therefore will be degrading to human health.

Mental health[edit]

While the physical health impacts of climate change are well known, the impact on mental health has only begun to be recognized in the last decade.^[34] According to 2011 in American Psychologist Clayton & Doherty, concluded that global climate change is bound to have substantial negative impacts on mental health and well-being, effects which will primarily be felt by vulnerable populations and those with pre-existing serious mental illness.^[35]

They identified three classes of psychological impacts from global climate change:^[36]

·         Direct - "Acute or traumatic effects of extreme weather events and a changed environment"

·         Indirect - "Threats to emotional well-being based on observation of impacts and concern or uncertainty about future risks"

·         Psychosocial - "Chronic social and community effects of heat, drought, migrations, and climate-related conflicts, and postdisaster adjustment"

In order to appreciate the impacts on psychological well-being an understanding and recognition of the multiple meanings and cultural narratives associated with climate change and the interrelatedness of climate change and other global phenomena, like increased population, is required.^[35] The psychological impacts of climate change can be divided into three classes; direct, indirect, and psychosocial. Direct impacts refer to the immediate or localized consequences of an environmental change or disaster, such as stress or injury. Indirect impacts are more gradual and cumulative and are experienced through the media and social interaction and communication. Psychosocial impacts are large-scale community and social effects, like conflicts related to migration and subsequent shortages or adjustment after a disaster. Climate change does not impact everyone equally; those of lower economic and social status are at greater risk and experience more devastating impacts.^[35]

Direct impacts on mental health, such as landscape changes, impaired place attachment, and psychological trauma are all immediate and localized problems resulting from extreme weather events and environmental changes.^[35] Research has shown that extreme weather events lead to a variety of mental health disorders from the impacts of loss, social disruption, and displacement.^[37] Further reinforced by Clayton & Dohert1y (2011), “[a]cute and direct impacts include mental health injuries associated with more frequent and powerful weather events, natural disasters, and adjustment to degraded or disrupted physical environments”.^[35]:265. For example, events such as wildfires and hurricanes can lead to anxiety and emotional stress, further exacerbated in already vulnerable populations with current mental health issues ^[37]

On the other hand, indirect impacts pertaining to mental health are more gradual and cumulative and are experienced through the media and social interaction and communication.^[35] For example, extreme weather events can pose indirect impacts through the migration of large communities due to stressors upon already limited resources.^[37] Some examples of common mental health conditions associated indirectly from these extreme weather events include: acute traumatic stress,post-traumatic stress disorder, depression, complicated grief, anxiety disorders, sleep difficulties, sexual dysfunction, and drug or alcohol abuse.^[37] Similarly, the devastating effects of the extreme weather event of Hurricane Katrina lead to a variety of mental health problems due to the destruction of resources.^[38] Many people impacted by Hurricane Katrina were left homeless, disenfranchised, stressed, and suffering physical illness.^[38] This strain on the public health system decreased access and availability of medical resources.^[38] Some climate change adaptation measures may prevent the need for displacement; however, some communities may be unable to implement adaptation strategies, and this will create added stress, further exacerbating already existing mental health issues.^[37] Extreme weather events and population displacement lead to limited availability of medications, one of the primary resources required to meet psychological and physical needs of those affected by such events.^[37]

Furthermore, one of the more devastating indirect impacts of climate change on mental health is the increased risk insuicide. Studies show that suicide rates increase after extreme weather events.^[38] This has been demonstrated in Australia, where drought has resulted in crop failures and despair to the Australian countryside.^[38] Farmers were left with nothing, forced to sell everything, reduce their stock, and borrow large sums to plant crops at the start of the season.^[38] The indirect consequences have caused a growing increase in depression, domestic violence, and most alarmingly, suicide.^[38] More than one hundred farmers in the countryside had committed suicide by 2007.^[38]

Psychosocial impacts are indirect impacts on social and community relationships. While some impacts result directly from an event caused by climate change, most are indirect results of changes in how people use and occupy territory.^[35] Extreme weather events can lead to the migration of large communities due to stressors upon already limited resources.^[37] Climate change affects the suitability of territory for agriculture, aquaculture, and habitation, which means that the experiences of people in particular geographical locations, as well as the geographical distribution of populations, will be altered.^[35]

Consequences of psychosocial impacts caused by climate change include: increase in violence, intergroup conflict, displacement and relocation and socioeconomic disparities. Based on research, there is a causal relationship between heat and violence and that any increase in average global temperature is likely to be accompanied by an increase in violent aggression.^[39] Diminished resources leads to conflict between two groups over remaining natural resources or the migration of one group to another group’s territory leading to conflict over rights and ownership of space.^[35] Furthermore, this can lead to civil unrest when governments fail to adequately protect against natural disasters or respond to their effects, causing people to lose confidence and trust in their government leading to backlash.^[40] Forced relocations and displacement, result in disruptions of geographic and social connections which can lead to grief, anxiety, and a sense of loss.^[41] Another consequence of psychosocial impacts is an increase in the disparity between those countries and people with adequate economic resources and those with fewer or in need of. Those nations and people with fewer resources will feel the impacts more strongly, as they have less ability to afford the technologies that would mitigate the financial and medical effects of climate change.^[35] Within nations, these individuals of lower socioeconomic status are more likely to become ethnic minorities, increasing ethnic tensions and inter group hostility. An example of such tension and hostility occurred in the aftermath of Hurricane Katrina where African Americans interpreted the government’s response to the disaster as indicating racism.^[35]