GEO217 Climate Change and Sustainability Lecture Notes PDF

GEO217 – Climate Change and Sustainability Mohamed Mahmoud, PhD Email: [email protected] & Tarek Abdel Shafy, PhD Email: [email protected] gu.edu.eg  Global Warming Impacts on Climate and Risk Factors More extreme weather events: storms, cyclone...

GEO217 – Climate Change and Sustainability Mohamed Mahmoud, PhD Email: [email protected] & Tarek Abdel Shafy, PhD Email: [email protected] gu.edu.eg  Global Warming Impacts on Climate and Risk Factors More extreme weather events: storms, cyclones, and flooding. Heat waves: more frequent, hotter, and longer. Rapid glacier melting: landslides, flash floods, and reduced water availability. Disturbed rainfall patterns: more droughts, more extreme precipitation events, more intense rainfall, floods, and disrupted water supply. Sea-level rise: saline water intrusion, loss of land and assets, and increased coastal flood frequency/severity. Air pollution: increase in levels of exposure to particulate matter and ozone increases hospitalizations and deaths for respiratory diseases (e.g., asthma) 1  The impact of climate change on the water cycle - Climate change is primarily a water crisis. We feel its impacts through worsening floods, rising sea levels, shrinking ice fields, and droughts. - Extreme weather events are making water more scarce, more unpredictable, more polluted, or all three. These impacts throughout the water cycle threaten sustainable development, biodiversity, and people’s access to water and sanitation. - Flooding and rising sea levels can contaminate land and water resources with saltwater or faecal matter, and cause damage to water and sanitation infrastructure, such as wells, toilets, and wastewater treatment facilities. - Droughts is destabilizing communities, and triggering civil unrest and migration in many areas. - Growing demand for water increases the need for energy-intensive water pumping, transportation, and treatment, and has contributed to the degradation of critical water-dependent carbon sinks, such as peatlands. - Water-intensive agriculture for food production, particularly meat, and for growing crops used as biofuels, can further aggravate water scarcity. 2  Climate change and water cycle o Climate change impacts the world’s water in complex ways. o Consider a water cycle diagram, global warming is altering nearly every stage in the diagram. o These changes will put pressure on drinking water supplies, food production, and property values. 3 Evaporation - Warmer air can hold more moisture than cool air. As a result, in a warmer world, the air will suck up more water from oceans, lakes, soil, and plants. The drier conditions could negatively affect drinking water supplies and agriculture. Precipitation - When all that extra warm, extra wet air cools down, it drops extra rain or snow to the ground. Thus, a warmer world means we get hit with heavier rain and snowstorms. Surface runoff (or overland flow) - Heavier rainstorms will also increase surface runoff — the water that flows over the ground after a storm. - This moving water may strip nutrients from the soil and pick up pollutants, dirt, and other undesirables, flushing them into nearby bodies of water. Those contaminants may muck up our water supplies and make it more expensive to clean the water to drinking standards. - Runoff that occurs on the ground surface before reaching a channel can be a non-point source of pollution. 4 Surface runoff (cont.) - In addition, as runoff dumps sediments and other contaminants into lakes and streams, it could harm fish and other wildlife. - Fertilizer runoff can cause algae blooms that ultimately end up suffocating aquatic critters and causing a stinky mess (known as eutrophication). - The problem is compounded by warming water, which cannot hold as much of the dissolved oxygen that fish need to survive. These conditions could harm fisheries, and make conditions unpleasant for folks who like to use lakes and streams for fishing, swimming, and other recreational activities. 5 Oceans - Warmer temperatures and increasing acidity are making life difficult for sea creatures. - In addition, many fish are moving poleward in search of cooler waters, which has implications for the fishing industry and people who like to eat fish. - And of course, as ice sheets and mountaintop glaciers melt, they’re dumping extra water into the oceans; the resulting sea level rise jeopardizes coastal properties around the world. 6 Snowpack - As snowpack melts in the spring, it slowly adds fresh water to rivers and streams and helps to replenish drinking water supplies. - However, as the air warms, many areas are receiving more of their precipitation as rain rather than snow. This means less water is being stored for later as snowpack. - In addition, the rain actually accelerates the melting of snow that’s already on the ground. The lack of snowpack can lead to drier conditions later in the year, which can be bad news for regions that rely on snowmelt to refill their drinking water supplies. 7  Implications of sea level rise - As the world warms, ice sheets and glaciers on land melt and flow into the ocean. The ocean itself also warms and expands, as it absorbs significant amounts of the heat trapped by the greenhouse gas effect. These changes cause the sea level to rise. - Future sea level rise depends on how quickly we reduce global greenhouse gas emissions. - The largest threat of future sea level rise comes from the possibility that the massive ice sheets in the Antarctic and Greenland could melt. In particular, the West Antarctic ice sheet is thought to be vulnerable to collapse. - In total, there is enough ice on the planet to raise sea levels by 70 m. It is difficult to predict at what level of warming this kind of dangerous change could occur; however, the risk grows as global temperatures increase. 8  The impact of climate change on Agriculture o Changes in the frequency and severity of droughts and floods could pose challenges for farmers and ranchers and threaten food safety. o Meanwhile, warmer water temperatures are likely to cause the habitat ranges of many fish and shellfish species to shift, which could disrupt ecosystems. o Overall, climate change could make it more difficult to grow crops and raise animals in the same ways and same places as we have done in the past. o The effects of climate change also need to be considered along with other evolving factors that affect agricultural production, such as changes in farming practices and technology. 9  Climate change impacts on crop yield o Climate change has an obvious impact on crop yields. For example, the effect of increased temperature will depend on the crop's optimal temperature for growth and reproduction. o In some areas, warming may benefit the types of crops that are typically planted there, or allow farmers to shift to crops that are currently grown in warmer areas. o Conversely, if the higher temperature exceeds a crop's optimum temperature, yields will decline. 10 o Higher CO2 levels can affect crop yields. Some laboratory experiments suggest that elevated CO2 levels can increase plant growth. However, other factors, such as changing temperatures, ozone, and water and nutrient constraints, may counteract these potential increases in yield. o Although rising CO2 can stimulate plant growth, it also reduces the nutritional value of most food crops. Rising levels of atmospheric carbon dioxide reduce the concentrations of protein and essential minerals in most plant species, including wheat, soybeans, and rice. This direct effect of rising CO2 on the nutritional value of crops represents a potential threat to human health. o Human health is also threatened by increased pesticide use due to increased pest pressures and reductions in the efficacy of pesticides. o More extreme temperatures and precipitation can prevent crops from growing. Extreme events, especially floods and droughts, can harm crops and reduce yields. o Dealing with drought could become a challenge in areas where rising summer temperatures cause soils to become drier. Although increased irrigation might be possible in some places, in other places water supplies may also be reduced, leaving less water available for irrigation when more is needed. o Many weeds, pests, and fungi thrive under warmer temperatures, wetter climates, and increased CO2 levels. 11  Climate change exaggerates food insecurity - Climate change is very likely to affect food security at the global, regional, and local levels. Climate change can disrupt food availability, reduce access to food, and affect food quality. - For example, projected increases in temperatures, changes in precipitation patterns, changes in extreme weather events, and reductions in water availability may all result in reduced agricultural productivity. - Increases in the frequency and severity of extreme weather events can also interrupt food delivery, and resulting spikes in food prices after extreme events are expected to be more frequent in the future. Increasing temperatures can contribute to spoilage and contamination. - In developing countries, adaptation options like changes in crop- management or ranching practices, or improvements to irrigation are more limited. 12  Climate change impacts on livestock o Changes in climate could affect animals both directly and indirectly. o Heat waves, which are projected to increase under climate change could directly threaten livestock. In 2011, exposure to high-temperature events caused over $1 billion in heat-related losses to agricultural producers. o Heat stress affects animals both directly and indirectly. Over time, heat stress can increase vulnerability to disease, reduce fertility, and reduce milk production. o Drought may threaten pasture and feed supplies. Drought reduces the amount of quality forage/feedstock available to grazing livestock. o Some areas could experience longer, more intense droughts, resulting from higher summer temperatures and reduced precipitation. For animals that rely on grain, changes in crop production due to drought could also become a problem. 13 - Climate change may increase the prevalence of parasites and diseases that affect the livestock. The earlier onset of spring and warmer winters could allow some parasites and pathogens to survive more easily. - Increases in CO2 may increase the productivity of pastures, but may also decrease their quality. Increases in atmospheric CO2 can increase the productivity of plants on which livestock feed. However, the quality of some of the forage found in pasturelands decreases with higher CO2. As a result, cattle would need to eat more to get the same nutritional benefits. 14 Climate change impacts on fisheries - Many aquatic species can find colder areas of streams and lakes or move north along the coast or in the ocean. Nevertheless, moving into new areas may put these species into competition with other species over food and other resources. - In addition to warming, the world's oceans are gradually becoming more acidic due to increases in atmospheric CO2. Increasing acidity could harm shellfish by weakening their shells, which are created by removing calcium from seawater. Acidification also threatens the structures of sensitive ecosystems upon which some fish and shellfish rely. - Some marine disease outbreaks have been linked to changing climate. Higher water temperatures and higher estuarine salinities have enabled an oyster parasite to spread farther north along the Atlantic coast. Winter warming in the Arctic is contributing to salmon diseases in the Bering Sea and a resulting reduction in the Yukon Chinook Salmon. - Finally, warmer temperatures have caused disease outbreaks in coral “bleaching”. 15 Thank You gu.edu.eg 16