10.3

Human influences on ecosystems

Human influences on ecosystems

The activities of human beings that have a significant impact on various ecosystems, including climate change, depletion of biological resources, and loss of biodiversity.

Climate change

The observed and projected increase in global temperatures and changes in climate patterns, often attributed to human activities such as burning fossil fuels and releasing greenhouse gases into the atmosphere.

Depletion of biological resources

The reduction or exhaustion of natural resources, such as land, food, and firewood, due to the increasing demands of a growing human population.

Loss of biodiversity

The decline in the variety of species and genetic diversity within each species, often caused by human activities such as overfishing, habitat reduction, and climate change.

Scientific journals

Publications that provide a platform for scientists to share their research findings and undergo a peer review process to ensure the validity and reliability of the research.

Peer review process

The evaluation of a scientific paper by other experts in the field to assess its quality, validity, and reliability before it is published in a reputable scientific journal.

Scientific conferences

Gatherings of scientists working in the same field to share data, discuss ideas, and present their research findings, allowing for collaboration and advancement in scientific understanding.

Greenhouse effect

The process by which greenhouse gases in the atmosphere trap heat radiated from the Earth's surface, maintaining a suitable temperature for life on Earth.

Temperature proxies

Indirect sources of data, such as tree rings, corals, ice cores, and peat bog data, used to infer past temperatures and study climate change over long periods of time.

Ice cores

Cylindrical samples of ice drilled from glaciers or ice sheets that provide a record of past climate conditions, including temperature and atmospheric carbon dioxide levels, dating back thousands of years.

Greenhouse effect

The natural process by which certain gases in the Earth's atmosphere trap heat, leading to the warming of the planet.

Evidence of rising global temperatures

Scientists have used temperature proxy records and statistical methods to show that global temperatures have been increasing steadily.

Mauna Loa data

The data collected from the Mauna Loa observatory in Hawaii shows a steady increase in atmospheric carbon dioxide levels from 1959 to 2006.

Reliability of Mauna Loa data

The Mauna Loa data is considered reliable because it is collected at regular intervals, is relatively free from local pollutants, and is believed to be representative of the Northern Hemisphere.

Law Dome ice cores

The data from the Law Dome ice cores in Antarctica also show changes in carbon dioxide concentration, similar to the temperature curves. This data provides a longer historical perspective on carbon dioxide levels.

Methane emissions from cattle

The digestion process of ruminant herbivores, such as cows, produces methane. Reducing the amount of methane emitted can be achieved by breeding or engineering new strains of grass that are more easily digested by cows.

Correlation between carbon dioxide levels and temperature

The data in fig H supports the theory that there is a close correlation between the rise in carbon dioxide and other greenhouse gases in the atmosphere and the increase in global temperatures.

Percentage increase in carbon dioxide from fossil fuel use

According to fig J, carbon dioxide levels from fossil fuel use increased by 80% between 1970 and 2004.

Impact of climate change on ecosystems

Climate change can affect the distribution of species around the world and cause long-term changes in weather and rainfall patterns.

Increase in extreme weather events

Statistical evidence suggests that there is an increase in extreme weather events, such as floods and droughts, linked to the rise in global temperatures.

Thinning of polar ice

A clear indication of global warming and potential cause of flooding.

Antarctic ice melting

In 2002, 500 billion tonnes of ice broke away from the Antarctic peninsula and melted into the sea.

Arctic sea ice retreat

The sea ice in the Arctic has been retreating by about 2.7% each decade since 1978.

Rising sea levels

Melting ice and warmer water result in increased volume of water in the seas and oceans, causing sea levels to rise.

Implications for human life

Around 100 million people live less than 1 meter above current sea levels, putting them at risk of displacement.

Effect of temperature on organisms

Temperature affects enzyme activity, which in turn affects the whole organism.

Optimum temperature for enzyme reactions

Enzymes have an optimum temperature for reactions, beyond which they denature and the reaction rate falls.

Effects on growth and reproduction

Increased temperature can affect the rate of growth and reproduction in organisms.

Threat to species in the tropics

A 1°C change in temperature could threaten the survival of up to 10% of all species, particularly in the tropics.

Changes in species distribution

Climate change can affect the range and distribution of many organisms.

Impact on disease spread

Global warming could lead to an increase in insect-borne diseases, such as mosquitoes and ticks.

Depletion of biological resources in farming

Farming practices can deplete soil mineral concentrations and soil biodiversity.

Depletion of fish stocks

Overfishing and unsustainable fishing practices are depleting fish populations worldwide.

Factors causing fish depletion

Global fishing fleet size, bottom trawling, and fishing through breeding seasons contribute to fish stock depletion.

Anthropogenic changes in the ocean

Changes in environmental conditions, such as water temperatures and pollution, can affect fish populations.

Conservation conundrum

Balancing human needs and conservation is a complex challenge for sustainable resource management.

Effective management of conflict

Sustainability requires managing the conflict between human needs and conservation.

Effect of human activities on climate change

Human activities, such as electricity production and deforestation, contribute to greenhouse gas emissions.

Need for international cooperation

Slowing greenhouse gas production and conserving vegetation require global cooperation and individual efforts.

Conservation of fish stocks

Efforts are needed to conserve and sustainably manage fish populations to prevent depletion and extinction.

Mesh size control

Adjusting the size of fishing nets to only catch larger fish.

Breeding season bans

Prohibiting fishing during the breeding seasons of different fish.

Strict fishing quotas

Imposing strict limits on the amount of fish that can be caught by fishing fleets and individual vessels.

Eco-friendly fishing methods

Encouraging the use of fishing methods that have less impact on ecosystems.

Ban on severely endangered fish

Prohibiting the catching of severely endangered species of fish.

Fish farming (aquaculture)

Cultivating fish and other seafood in controlled environments.

Fish farming's global impact

Approximately 47% of fish consumed worldwide in 2012 was produced through aquaculture.

Environmental concerns of fish farming

Fish farms contribute to greenhouse gas emissions and often rely on other fish for feed.

Alternative fish feed

Exploration of alternative food sources, such as marine algae, to reduce the environmental impact of fish farming.

Importance of fish farming

Fish farming plays a crucial role in producing sustainable fish stocks and preserving coastal waters and oceans' biological resources.