Chapter summary
Climate, biodiversity and disease ecology, at a glance
Scan the key ideas, or hide the answers and try to recall them.
01
Human activity changes carbon flows
Why can releasing an old carbon store change the atmosphere?
Key idea and reminders
Human activities increase greenhouse-gas accumulation by releasing stored carbon and altering biological sinks and methane production.
- Fossil burning transfers stored carbon to CO2.
- Deforestation removes stocks and uptake capacity.
- Food choices affect land use, energy and methane.
Keep in mind: Their central greenhouse role is absorption and re-emission of outgoing infrared radiation, changing energy loss to space.
02
Compare whole-system carbon footprints
Why is zero exhaust not the same as zero life-cycle emissions?
Key idea and reminders
A fair footprint comparison uses a common functional unit and includes construction, fuel, land use and operation where relevant.
- Operational and life-cycle emissions differ.
- A common functional unit makes comparisons meaningful.
- Land-use change can dominate a footprint.
Keep in mind: Net impact depends on land-use change, cultivation, processing, energy inputs and regrowth assumptions.
03
Warming changes habitats and interactions
How does a physical change become a biological stress?
Key idea and reminders
Climate alters temperature, water and habitat conditions, with consequences for survival, species interactions and food chains.
- Land-ice melt and thermal expansion raise sea level.
- Species movements differ and can disrupt interactions.
- Thawing organic matter can create greenhouse feedback.
Keep in mind: Movement constraints and different responses can separate interacting species and leave some with no suitable habitat.
04
Mangroves store carbon and protect coasts
How can one ecosystem reduce emissions and reduce damage?
Key idea and reminders
Mangroves store carbon in biomass and sediments while their physical structure reduces wave energy and stabilises shores.
- Biomass and sediments store carbon.
- Waterlogging can slow decomposition.
- Roots reduce wave energy and stabilise sediment.
Keep in mind: Mangrove function depends on coastal hydrology, sediments, suitable species and ecosystem establishment.
05
Food supply and tropical biodiversity
Why does losing a wild population matter beyond its current use?
Key idea and reminders
Climate stress threatens production and erodes biological options for future food resilience and biomedical discovery.
- Food stress includes direct physiology and indirect ecological effects.
- Genetic diversity preserves breeding options.
- Biodiversity is a potential biomedical resource, not a catalogue of guaranteed cures.
Keep in mind: It can support ecological functions and preserve genetic or biochemical options not yet used.
06
Temperature and the Aedes life cycle
Why does warming help development only within a suitable range?
Key idea and reminders
Moderate warming can speed insect metabolism and development, but heat beyond tolerance reduces survival and does not increase risk indefinitely.
- Egg -> aquatic larva -> aquatic pupa -> adult.
- Temperature affects metabolism and development.
- Too much heat can reduce survival.
Keep in mind: Thermal tolerance, water availability and survival impose limits and can reverse the response.
07
Warming and disease-range shifts
What else is needed besides a warmer climate for transmission to occur?
Key idea and reminders
Climate can alter vector suitability and season length, but transmission also needs the correct vector, pathogen, hosts and contact opportunities.
- Dengue: virus and Aedes.
- Malaria: Plasmodium and Anopheles.
- Range suitability is necessary in some settings but not sufficient for transmission.
Keep in mind: Malaria involves Plasmodium parasites and Anopheles vectors; dengue involves a virus and Aedes vectors.