BIOL 204: 34: Global Climate Change

Mechanisms of Greenhouse gases

are processes by which gases such as carbon dioxide, methane, and nitrous oxide trap heat in the Earth's atmosphere, leading to an increase in global temperatures and impacting climate patterns.

Greenhouse Effect

is the process by which greenhouse gases absorb and emit radiant energy, resulting in the warming of the Earth's surface and atmosphere.

• Solar radiation enters atmosphere, some is reflected, and some is absorbed by the Earth’s surface, warming it up

• Heat is emitted as infrared radiation, some is lost in space, but much is trapped by greenhouse gases and retained in the atmosphere

• Longer wavelength energy retained more by atmosphere

Albedo Effect

is the measure of how much solar energy is reflected by the Earth's surface, specifically by clouds, ice, and land. A higher albedo means more reflection and less absorption of heat, impacting global temperatures.

Most common greenhouse gases

• Carbon Dioxide (CO2)

• Methane (CH4)

• Nitrous Oxide (N2O)

• Ozone (O3)

• Water vapor (H2O)

Causes of CO2 increase

Largely due to burning fossil fuels. Other significant contributors include deforestation, industrial processes, and land-use changes.

• Long-term increase in global temperature matches change in atmospheric CO2

Low Certainty Predictions

• Amount of sea level rise

• Changing precipitation

• Changing extreme events

High Certainty events

• Rising Temperature

• Ocean Acidification

Pteropods

Small, swimming marine mollusks known as sea butterflies, important for ocean ecosystems and impacted by ocean acidification. “Potato chips of the sea” that serve as a food source for many marine animals and are vulnerable to changes in ocean chemistry.

Ecological responses: shifts in species ranges

Changes in the geographic distribution of species due to climate change, affecting biodiversity and ecosystems.

• Ex:

  • Plants moving up the Alps

  • European butterflies are moving poleward

Species unlikely to shift geographical ranges at speed of climate change

• Most plants

• Small Mammals

• Freshwater Bivalves

Acclimate

The process by which an organism adjusts to changes in its environment, such as temperature or humidity, enhancing its ability to survive in altered conditions.

Evolutionary Responses: Local Adaptation to Temperature Increase

The ability of species to evolve traits that enhance survival and reproduction in response to rising temperatures, leading to adaptations that occur over generations.

• Ex: two-spot ladybirds:

  • proportion of melanic forms decreased with local temperature

  • change in phenotype is genetic in origin

• In many cases, evolution might be too slow unless the strength of selection is very strong

Climate change and society

The interaction between climate change impacts and societal responses, including adaptations in policies, economies, and communities to mitigate environmental changes.

• ex: pacific fishing predicted to be greatly reduced

• most climate change models predict net decline in terrestrial food production

Potential Solutions to Climate change

• Reduce current greenhouse gas emissions

  • reduce traveling

  • use solar/wind energy

  • eat locally

• Decrease societal inequality

  • Avoid food scarcity

  • provide financial incentives to relocate people to avoid risk from catastrophic floods and droughts

• Proactive approach to ameliorate ecological impacts

  • establish additional protected areas to allow dispersal of organisms

  • human-aided dispersal of organisms

  • establish no-take zones in marine ecosystems