Introduction to Environmental Science Environmental Concepts The environmental system  The natural environment, commonly referred to simply as the environment, is a term that encompasses all living and non-living things occurring naturally on Earth or some region thereof The environmental system  The concept of the natural environment can be broken down into a few key components:  Complete ecological units that function as natural systems without massive human intervention, including all vegetation, animals, microorganisms, soil, rocks, atmosphere and natural phenomena that occur within their boundaries  Universal natural resources and physical phenomena that lack clear-cut boundaries, such as air, water, and climate, as well as energy, radiation, electric charge, and magnetism, not originating from human activity The environmental system  The environmental system may be understood in an ecological sense as the set of interactions between the elements of the biosphere, which includes the atmosphere, the hydrosphere, the lithosphere and the ecosphere The environmental system  The atmosphere is a mixture of nitrogen (78%), oxygen (21%), and traces (remaining 1%) of carbon dioxide, argon, water vapor and other components  The atmosphere is approximately 1,100 km high, the stratosphere (10 to 50 km) and the troposphere (less than 10 km) are the main atmospheric interactors of the biosphere  The atmosphere is a prime mean for the spatial diffusion of pollutants and a temporary mean of their accumulation The environmental system  The hydrosphere is the accumulation of water in all its states (solid, liquid and gas) and the elements dissolved it in (sodium, magnesium, calcium, chloride and sulphate)  97% of the water forms the oceans, 2% is ice (north and south poles) and 1% forms rivers, lakes, ground water and atmospheric vapor  It covers around 71% of the earth's surface and is an important accumulator of pollutants and a significant vector of diffusion The environmental system  The lithosphere is the thin crust between the mantle and the atmosphere Although the lithosphere is around 100 km thick, only km of it can be considered in interaction with the biosphere  Main constituents are oxygen (47%), silicon (28%), aluminum (8%), iron (5%), calcium (4%), sodium (3%), potassium (3%) and magnesium (2%) in a crystalline state  The lithosphere is the main source of pollutants and a permanent accumulator Some are naturally released through sources like volcanic eruptions, while others like fossil fuels are the result of artificial extraction and combustion The environmental system  The ecosphere is the set of all living organisms, including animals and plants  They are temporary accumulators (like lead) and sources for pollutants (natural forest burning) in a very complex set of relationships with the atmosphere, hydrosphere and lithosphere The Environmental System Population & consumption  Human population growth exacerbates all environmental problems  The growth rate has slowed…but we still add more than 200,000 people to the planet each day  Our consumption of resources has risen even faster than our population growth  Life has become more pleasant for us so far  However, rising consumption amplifies the demands we make on our environment We face challenges in biodiversity • Human actions have driven many species extinct, and biodiversity is declining dramatically Biodiversity loss may be our biggest environmental problem; once a species is extinct, it is gone forever Habitat Fragmentation Habitat fragmentation is the process by which human activity breaks natural ecosystems into smaller and smaller pieces of land called habitat fragments Habitat Fragmentation (cont’d)  one concern is whether remaining habitat is of sufficient size and quality to maintain viable populations of wild species;  large predators, such as grizzly bears, and migratory species, such as bison, require large expanses of continuous habitat;  habitat fragments are often compared to islands, and principles of island biogeography are often applied in habitat conservation The Millennium Ecosystem Assessment • The most comprehensive scientific assessment of the condition of the world’s ecological systems • Major findings: • Humans have drastically altered ecosystems • These changes have contributed to human wellbeing and economic development, but at a cost • Environmental degradation could get much worse • Degradation can be reversed, but it requires work We face challenges in agriculture • Expanded food production led to increased population and consumption • It’s one of humanity’s greatest achievements, but at an enormous environmental cost • Nearly half of the planet’s land surface is used for agriculture • • • • Chemical fertilizers Pesticides Erosion Changed natural systems We face challenges in pollution • Waste products and artificial chemicals used in farms, industries, and households Each year, millions of people die from pollution We face challenges in climate • Scientists have firmly concluded that humans are changing the composition of the atmosphere • The Earth’s surface is warming • Melting glaciers • Rising sea levels • Impacted wildlife and crops • Increasingly destructive weather Since the Industrial Revolution, atmospheric carbon dioxide concentrations have risen by 37%, to the highest level in 650,000 years Our energy choices will affect our future • The lives we live today are due to fossil fuels Machines • Chemicals • Transportation • Products • Fossil fuels are a one-time bonanza; supplies will certainly decline • We have used up ½ of the world’s oil supplies; how will we handle this imminent fossil fuel shortage? Environmental Impact Determined by three factors:  Number of people (P)  Number of resource units/person (C)  Amt of environmental degradation produced per unit of resource (E) PxCxE=I SEPM Photo CD-10, Environmental Science 1, 1997 Sustainable solutions exist  We must develop solutions that protect both our quality of life and the environment  Organic agriculture  Technology  Reduces pollution  Biodiversity  Protect species  Waste disposal  Recycling  Alternative fuels The “ecological footprint”  The environmental impact of a person or population  Amount of biologically productive land + water  for raw materials and to dispose/recycle waste  Overshoot: humans have surpassed the Earth’s capacity We are using 30% more of the planet’s resources than are available on a sustainable basis! Ecological footprints are not all equal  The ecological footprints of countries vary greatly  The U.S footprint is almost times greater than the world’s average  Developing countries have much smaller footprints than developed countries Are things getting better or worse? • Many people think environmental conditions are better • Cornucopians: Human ingenuity will solve any problem • Some think things are much worse in the world • Cassandras: predict doom and disaster • How can you decide who is correct? • Are the impacts limited to humans, or are other organisms or systems involved? • Are the proponents thinking in the long or short term? • Are they considering all costs and benefits? [...]... erosion and species extinction  Environmental changes threaten long-term health and survival (i.e., id est; (e.g., exempli gratia) Environmental science - Definition  Environmental science is the science of the interactions between the physical, chemical, and biological components of the environment, including their effects on all types of organisms  Environmental Science: Systematic study of our... Environmental Science: Systematic study of our environment and our place in it  Environmental science includes specific areas of study, such as: biology, ecology, and environmental engineering  Environmental science is the study of:  How the natural world works  How the environment affects humans and vice versa HISTRORY OF ENVIRONMENTAL SCIENCE Malthus’ Theory  Context  Thomas Malthus (1766-1834) in his... agricultural techniques enough to answer demand?  The next 25 years will be crucial and will bring forward answers to these questions Contemporary Issues  Relevance of the Malthusian theory  The work of Malthus continues to be important to demographers:  Influence of many contemporary theorists from various academic disciplines  Built upon Malthus’s ideas and linked them to modern sciences ... people who are born, live and work His followers have failed to produce sound projections They lacks sound data and sound logic 3 Contemporary Issues  The Malthusian crisis today  Demographic growth:    Between 1960 and 2000, three billion persons were added to the global population To sustain this growth, agricultural resources had to be doubled Required housing space surpassed all that was constructed... Malthusian crisis today  Agricultural growth: Between 1960 and 1990, grain yields has increased by 92% while cultivated surfaces have only increased by 8%  Foresee a limit to growth in agricultural production  Consumption growth  Environmental degradation  Contemporary Issues  Relevance of the Malthusian theory  Was Malthus right or the trend in agricultural production will again increase to surpass... of children in the industrializing societies Malthusian Crisis  The Malthusian Crisis has not occurred  Failed to account for improvements in technology:  Enabled food production to increase at rates greater than arithmetic, often at rates exceeding those of population growth  Enabled to access larger amounts of resources  Enabled forms of contraception Malthus and his followers are mistaken.. .Introduction  What is an environment?  What is Environmental Science? The Environment  Environment: Circumstances and conditions that surround an organism or group of organisms Social and cultural conditions that affect an individual... non-linear (exponential)  Written during a period of weak harvests  Context  Took notice of famines in the Middle Ages, especially in the early 14th century (1316)  From the data he gathered, population was doubling every 25 years  Over a century’s time, population would rise by a factor of 16 while food rose by a factor of 4 1 Concept Malthus’ Theory of Population Growth  In 1798 Thomas Malthus... highlights the problem of too many mouths to feed, rather than the uneven distribution of resources; Malthus (cont.) Population grows geometrically… Population exceeds carrying capacity… Population is kept in “check”– preventative and/or positive checks “The Malthusian Trap” Subsistence Economy Equilibrium (Births = Deaths) New Technology Higher incomes, higher births and lower deaths Return to Subsistence Populations... Environment: the total of our surroundings • All the things around us with which we interact: • Living things Animals, plants, forests, fungi, etc • Nonliving things • Continents, oceans, clouds, soil, rocks • Our built environment • Buildings, human-created living centers • Social relationships and institutions • Humans and the world around us  Humans change the environment… in ways not fully understood 