Climate Change Flashcards
How is climate changing?
- always undergone periods of stability and periods of change
- been warmer than today, ecosystems are adapted for current conditions
- rapid climate change associated with mass extinction
- after cooling, we are experiencing rapid warming
- since 1780s start of industrial revolution
- past warming = slower
Past warming has been slower
data
- 4 - 7°C over ~5,000 years when moving out of ice ages
- Now ~ ten times faster
What are we at now in relation to preindustrial levels?
Now at ~1.2°C above preindustrial levels
What is the effect of greenhouse gases in atmosphere?
prevent sun’s heat from escaping - essential for life
What are anthropogenic -related increases in greenhouse gasses leading to?
rapid increases in global temperatures
What has extensive climate modelling shown?
humans are driving rapid warming
What has overwhelming scientific consensus shown?
(~97%)
Climate change is caused by human-induced emissions of greenhouse gases
no scientific body of national or international standing disagrees with this view
What is main greenhouse gas driving temperature rise?
CO2
What was the previous ppm (CO2) and now?
high 300 parts per million ~300,000 years ago
now: average ~424ppm May 2023
What is the rise in CO2 ppm caused by mainly?
fossil fuel burning
What is the next largest contributor after CO2?
Methane
How much has atmospheric methane increased by?
about 150% since 1750
What are the sources of methane?
- Livestock production - belch methane
- waste management
- release from sediments e.g. in Arctic, previously encased in permafrost
What else is changing other than temperatures?
warming not occurring evenly across globe
rainfall patterns - changing rapidly
sea ice melting, especially in Arctic - oceans are becoming more acidic
increase in extreme heat, heavy rainfall and agricultural/ecological drought
2021 IPCC report
Current and estimate of temperature above preindustrial levels
currently at - 1.2°C above preindustrial levels
could reach 4°C by the end of the century unless large changes are made on a global level
What are the responses to climate change for species?
environmental change alters the adaptive peak of high fitness
species need to change accordingly or risk extinction
they can change:
- spatial distribution
- local phenotype (including behaviour)
- phenotype (timing of life events)
What are the responses to climate change?
extinction
geographic range shifts
altered phenologies
biome regime shifts
When would extinction occur in relation to climate change?
- if species unable to change rapidly
What do future extinctions relate to in terms of climate change?
depend on extent of climate change
and assumptions made when making predictions e.g. does extinction occur after 100% habitat loss, or before this?
Where to predictions of extinction come from?
models of species distribution under predicted future climatic conditions
What is the mean extinction risk from studies?
7.9% with a 95% confidence interval of 6.2% to 9.8%
What taxonomic groups and locations are more vulnerable to extinction?
- amphibians and reptiles = terrestrial endotherms = vulnerable to temp change and may have temp-dependent sex determination
- areas w/ many endemic species that have small ranges = particularly vulnerable
Within amphibians and reptiles, what are the most important determinants of extinction risk?
distribution and population size
How many extinctions so far?
few, 33 of 872 (3.7%) of extinctions from IUCN cite climate change
How much has climate change increased extinction risk by so far?
average of 14%
Are local extinctions common or uncommon?
much more common
What was the first species to go extinct due to anthropogenic climate change?
The Bramble Cay melomys (Melomys rubicola)
Where are species moving as temperatures rise? (geographic range shifts)
away from equator as temperatures rise
What did Hickling et al. (2006) find out? (geographic range shifts)
84% of 329 British species showed clear evidence of northward range shifts between 1960 and 2000
not always a habitat for them to move into
What species are shifting? (geographic range shifts)
marine species = shifting, probably faster than terrestrial species
What species are the most mobile? (geographic range shifts)
(e.g. phytoplankton) moved 470km per decade
What effect will geographic range shifts have?
effect food web
What is occurring in many species? (Altered phenologies)
changes in timing events (e.g. reproduction)
What is the best record of altered phenologies?
from Japanese cherry blossom (Prunus jamasakura)
Are altered phenologies a threat to biodiversity?
not on their own
When do altered phenologies become a threat to biodiversity?
when changes reduce fitness
e.g. by leading to population asynchronies
Example of altered phenologies affecting fitness
timing of reproduction of great tits = not changes with climate, but peak data for caterpillars (their food source) has
leads to reduction in fitness of late-laying birds
Example of biome regime shifts
woody plants started growing at high latitudes (e.g. Arctic tundra) and altitudes (e.g. previously alpine meadows/heathlands)
e.g. heather heathland in Spanish mountains replaced by oak forest
Where are kelp forests dominating? (biome regime shifts)
dominated along western coast of Australia until 2011, when extreme heat caused the kelp to die off
replaced with different community that suppresses kelp
What have the heatwaves caused? (Biome regime shifts)
repeated mass bleaching of the great barrier reef in recent years
Coral reefs data (biome regime shifts)
best case scenario (1.5°C warming) 70-80% loss
>99% loss at 2°C warming
Other effects than on biodiversity?
will we have enough food?
will our ecosystem services still function?
we need to adapt rapidly
Types of managing effect of climate change
International agreements
Governmental action
Refugia and safe havens
Optimising migration pathways
Assisted colonisation
Building evolutionary resilience
Climate mitigation and green infrastructure
What are the most important international agreements as a management of climate change effects?
- The Paris Agreement: a legal binding international treaty on climate change
- adapted by 196 Parties at COP 21 in 2015
- its goal = to limit global warming to well below 2°C, preferably to 1.5°C
- requires substantial cuts in greenhouse gas emissions
pledges and targets aren’t sufficient enough to reduce global warming to 1.5°C
and current policies are way off
Future pledges = expected to bring us closer
- At COP26 Glasgow 2021 some more ambitious commitments were made
- COP27 Egypt 2022 shift to loss & damage finance and implementation
- COP28 in United Arab Emirates 2023 is coming up
How much have per capita fossil fuel CO2 emissions changed by? (Governmental action)
almost halved in UK since 1970s
not including emissions associated with imports
How much has the UK reduced fossil fuel CO2 emissions with trade included? (Governmental action)
reduced fossil fuel CO2 emissions by 39% since peak in early 2000s
Where were species able to survive during past climatic shifts? (Refugia and safe havens)
many species able to survive in refugia; areas that avoided worst impacts of climate change
Where are refugia and safe havens?
- describe species’ modern distributions in terms of the climate
- search for the same climatic niche using forecast future climate conditions
e.g. snow leopards
Optimising migration pathways
- species need to reach refuges
- need to ensure migration corridors exist
- e.g. Yellowstone to Yukon (Y2Y) project
- Covers 2 countries, 5 U.S. states, 2 Canadian provinces, the land of > 30 Native American and First Nation governments
- Named by the IUCN-World Conservation Union as one of world’s leading conservation initiatives
Assisted colonisation
Should we help move species to new suitable habitats?
- e.g. critically endangered western swamp turtle (Pseudemydura umbrina) = moved 250km outside current range in Australia to cooler areas after its swamps started drying up
Or are we opening a Pandora’s box of invasive species?
- e.g. introducing disease-free Tasmanian devils (Sarcophilus harrisii) to an island in 2012 to protect them from facial tumor disease
- Tasmanian devils did well, but wiped out some of island’s breeding sea bird colonies
Assisted colonisation may be useful tool in some cases, but careful risk assessment is required
Building evolutionary resilience
- some species evolve to cope w/ changing climate
- maximise chances this occurs; need to ensure sufficient genetic variation by: increasing population sizes, locating and protecting areas of high genetic diversity; translocate genes; assisted evolution; identity species with low adaptive potential
translocate genes = e.g. translocate individuals from warmer parts of species range to cooler parts, or translocate corals that show resistance to bleaching
assisted evolution = captive breeding individuals with greater ability to survive climate change, e.g. corals
identify species with low adaptive potential = for other conservation measures
What has an important role to play in halting climate change? (Climate mitigation and green infrastructure)
biodiversity
e.g. carbon sequestration via reforestation, protecting from deforestation, and ecosystem restoration
e.g. biodiversity can protect us from climate-related disasters
What project aims to use green infrastructure to absorb water to prevent floods? (Climate mitigation and green infrastructure)
China’s ‘sponge city’ project aims to use green infrastructure to absorb water, preventing floods
Components of climate change
Mean levels, variability, maxima and minima, frequency, predictability, seasonality
Greenhouse gases
- concentrations of CO2, CH4, N2O
Temperature
- air, sea surface, freshwater
Precipitation and ice
- rain and snowfall, ice cover
Ocean dynamics
- sea levels, water currents
Ocean acidification
- pCO2, pH
Extreme events
- floods, droughts, storms, fires
Levels of biological response
Genes -> Species -> Communities
Evolution
- mutation, natural selection, speciation
Organismal physiology
- fecundity, survival, circadian rhythms, disease susceptibility
Population dynamics
- recruitment, age structure, sex ratios, abundance
Species distributions
- ecological niches, range size
Interspecific interactions
- competition, predation, parasitism, mutualism
Ecosystem services
- biomass production, water availability, pest control, tourism
