D4.3 Climate change Flashcards
Define climate
Climate = a long-term average of weather (over 20-30 years), not year-to-year variations.
Define climate change
Climate change = a long-term change in global or regional climate patterns, caused by natural or human factors, such as increased levels of atmospheric carbon dioxide produced by the use of fossil fuels
Define Greenhouse effect
Greenhouse effect = heating caused by atmosphere on Earth’s surface bc certain atmospheric gases absorb & emit infrared radiation
Define Greenhouse gas
Greenhouse gas = a gas that contributes to greenhouse effect by absorbing infrared radiation
Define global warming
Global warming = an increase in global average temp of Earth’s surface & atmosphere
Define Albedo
Albedo = fraction of solar radiation reflected by a surface or object, often expressed as a percentage
Define Landfast ice
Landfast ice = sea ice that is ‘fastened’ (attached) to coastline, to sea floor along shoals or grounded icebergs.
Define upwelling
Upwelling = process where deep, cold water rises toward surface of ocean
Define upslope range shift
Upslope range shift = process where montane species move higher up mountains in response to recent temp increases
Define afforestation
Afforestation = establishment of forests in an area where there was no previous tree cover (NOT reforestation)
Define carbon sequestration
Carbon sequestration = capture & storage of carbon dioxide from atmosphere by physical or biological processes such as photosynthesis
Define photoperiod
Photoperiod = period of time each day during which an organism receives light i.e. day lengths
Define phenology
Phenology = research into timing of seasonal or cyclical biological events, such as flowering, budburst & bud set, bird migration & nesting
Define life cycle
Life cycle = series of changes in the life of an organism, including reproduction
What are the two causes of climate change?
Burning fossil fuels & Deforestation
What explanation is given for there being more frequent torrential downpours and deeper droughts?
Temperature rise from global warming cause more evaporation of water. From sea this causes more clouds, & more rain-storms. From land this evaporation causes more drought, for longer periods.
What gases make up Earth’s atmosphere?
- Nitrogen 78%
- Oxygen 21%
- Argon 0.9%
- Carbon 0.042%
What is the greenhouse effect?
Earth’s atmosphere acts as a greenhouse, in that gases such as methane or carbon dioxide absorb long-wave radiation (infrared radiation) upon reflection from Earth’s surface. This greenhouse effect keeps Earth much warmer than it otherwise would be, & without it temp on Earth would be below zero Celsius.
Draw diagram to show how these gases contribute to the warming effects that wrap up the Earth.
What are the steps to greenhouse effect?
Radiant energy reaching Earth from Sun is mainly visible light with some ultra-violet & shorter wavelength infrared radiation (together termed shortwave radiation). This shortwave radiation is largely transmitted through atmosphere to directly warm up sea & land. Some is reflected by clouds before it reaches surface. Whenradiation from Sunhits Earth, it isradiated backfrom Earth’s surface at longer wavelengths towards space. AGHGis a gas thatabsorbsthis re-radiated radiation,trapping it in Earth’s atmosphereso that it is not lost to space. GHG in atmosphere have a similar effect to glass in agreenhouse, hence termGHG, & their effect being known asgreenhouse effect. Greenhouse effect is important to ensure that Earth iswarm enough for life; if it were not for insulating effect of greenhouse gases, Earth would see similar dramatictemp fluctuationsto its neighbouring planets. Temp on Mars range between 20°C & −153°C. There are many GHG including CO2 & Methane. It is thought that increasing levels of CO2 & methane are entering atmosphereas a result of human activities, leading to increased rates of atmospheric warming
Atmospheric warming, & therefore CC, for which humans are thought to be responsible is known asanthropogenic CC
What are the most significant GHG?
Most significant GHG are water vapour, carbon dioxide & methane. Other abundant gases of atmosphere (e.g. O2 or nitrogen) are not GHG because they don’t absorb longer-wave radiation, so they don’t contribute to absorbance of radiation.
How can we measure the GHG levels across time?
Long-term records of changing levels of GHGs (& associated CC) are based on evidence from ice cores drilled in Antarctic and Greenland ice sheets. Ice has formed from accumulation of layer upon layer of frozen snow, deposited & compacted over thousands of yrs. Gases from surrounding atmosphere were trapped as layers built up. Data on composition of bubbles of gas obtained from diff layers of these cores from Vostok (East Antarctic) Ice Sheet provide a record of how CO2 & methane concentrations have varied over a period of 400000 yrs. Similarly, variances in conc of oxygen isotopes from same source indicate how temp has varied during same period.
What causes the enhanced greenhouse effect?
While cell respiration & some natural forest fires naturally release CO2 into atmosphere, enhanced greenhouse effect is caused by combustion of fossil fuels in internal combustion engines & biomass (coal power plants, etc…), forest fires & deforestation.
How have levels of carbon dioxide changed through the years?
AtmosphericCO2
levelshavefluctuated throughout Earth’s historydue to events such as volcanic eruptions & weathering of limestone rocks. Sinceindustrial revolution, however, atmospheric carbon dioxide levels haverisen to their highest in Earth’s history. Industrial revolution began in late 1700s whencombustion of fossil fuelsto powerfactories, transport, &homesbecame commonplace. Fossil fuel combustion releasesCO2.
What is the correlation between carbon dioxide levels and global temperature? And what releases CO2?
A clearcorrelationcan be seen between increasinglevels of CO2 since the industrial revolution&increasing global temp, providingevidencefor role of human activities in causing global warming. Note that acorrelation alone is not enough to prove causation, but this evidence can be taken alongside what we know about GHG & other evidence to provide a growing body of proof. In addition to burning of fossil fuels, CO2 is also released into atmosphere whennatural stores of carbon are damaged or destroyedby human activities
These carbon stores are known ascarbon sinks. Carbon sinks include trees, soils, peat bogs, & oceans. Deforestation, soil degradation, peat harvesting, & ocean warming all contribute to addition of CO2 to atmosphere.
Who and what releases CH4?
Melting permafrost releases methane through methanogens in swamps & waterlogged soils, as well as landfill sites where organic wastes have been dumped. Methanogenic bacteria in guts of ruminants release methane during excessive cattle farming. Natural wetlands & paddy fields also release methane.
What is methane?
Methane(CH4) is a simplehydrocarbon. It is present as agasin atmosphere, & underground, & is main component ofnatural gasfossil fuel.
Where does methane get produced?
Methane can be produced bynaturally occurring processesin some types of bacteria, but levels have risen significantly in last 150 yrs due to human activities. Methane can be produced by several human activities. Methane is released fromguts of ruminant mammals,such as cattle, that are farmed by humans. Intensive farming of such animals has greatly increased their contribution to atmospheric methane. Landfill sitesrelease methane when organic matter such as food waste decomposes
Extraction of fossil fuels from undergroundreleases methane.
Anaerobic bacteria in waterloggedrice paddy fieldsrelease methane. In addition to the list above, the warming of poles that results from global warming also leads torelease of methane from natural storessuch as permafrost
Permafrost is ground that remains frozen all yr round.
What is a positive feedback? And how is it linked to global warming?
Positive feedback is when end product of a process results in the amplification of process that created it. Global heating is associated with a number of positive feedback cycles.
What is a negative feedback? And how is it linked to global warming?
Negative feedback is when end product of a process results in reduction of process that created it. There are very few changes that bring about negative feedback in global warming.
How does positive feedback loops lead to global warming?
Positive feedback is any mechanism in a system that leads toadditional & increased change away from equilibrium. Positive feedback loops occur when output of a process feeds back into systemin a way that moves system increasingly away from average state. In this way,positive feedback is destabilising;itamplifies deviationfrom equilibrium &drives systems towards a tipping pointwhere the state of system suddenly shifts to a new equilibrium. Global warming has a positive feedback effecton Earth & its atmosphere. This means thatglobal warming leads to more global warming, whichfurther increases global warming, etc. There are several factors that contribute to positive feedback cycle of global warming.
Positive feedback mechanisms involve, e.g. , increasing temperatures, thawing permafrost & release of methane. As methane is a GHG, it has potential to increase temp, thereby reinforcing rise in temp.
Explain how the water cycle is accelerated by changes in the heat content of the atmosphere (caused by an increase of greenhouse gases).
Explain how the melting of snow and ice is an example of positive feedback.
Extent to which a surface reflects light is known as itsalbedo; higher albedo, more light is reflected. Light coloured surfaces such as snow & ice have a high albedo, while dark surfaces such as rock & soil have a low albedo. As polar ice caps meltdue to global warming, earth’s overall albedo decreases, &more of sun’s energy is absorbedby exposed rock, soil, & dark surface of oceans; thisincreases global warming. This cycle continues, further increasing global warming.
Why is the melting a positive feedback?
Methane is bubbling up from thawed permafrost at bottom of lake through ice at its surface. Positive feedback further affects permafrost. Permafrost is ground that remains frozen all year round. As global heating accelerates, permafrost melts & waterlogged detritus begins to decay, releasing methane. This in turn further accelerates global warming. (Melting permafrost can also lead torelease of methane(CH4), a potent GHG.
This is due toactivity of methanogenic microorganismsin frozen soil, whichincreases as permafrost melts. Methanogenic microorganisms are species ofarchaeathatproduce methaneas part of their metabolism)
Explain how droughts and forest fires further accelerates global warming?
Increased heating of atmosphere caused by positive feedback cycle has brought about CC with an increased number of droughts & wildfires. As global warming increases frequency of extreme weather events,droughts occur more often. Dry vegetation that results from drought can catch fire easily, &wild fires become more likely. Combustionof plant materialreleases carbon dioxideinto atmosphere, where it increases global warming. Resultingreduction in number of photosynthesising plants(carbon sinks) means thatless CO2 is removedfrom atmosphere.
What is a tipping point? And how is it reached?
When all environmental changes & positive feedback cycles overwhelm resilience of an ecosystem, a tipping point is reached whereby ecosystem is converted from one stable form to another.
What is Boreal forest?
Boreal (coniferous) forests (also known as Taiga) in northern areas of world (Alaska, Canada, Russia) are important carbon sinks, as cold temp slow down cellular respiration of detritus & other organism, while photosynthesis captures CO2 in tree biomass. They store more CO2 than tropical rainforests globally as they are distributed over a greater area. Boreal forests, ortaiga, form a biome that covers much of North America, Europe, & Russia, & though they have relatively lowproductivity, these forests are animportantcarbon sinkdue to their size.
What effect has climate change on the boreal forest?
Climate change has brought these forests to a tipping point, in where they might turn from carbon sinks to carbon sources. Warm, dry summers have led to droughts & forest fires releasing CO2 stored in detritus in large quantities, & preventing it to store carbon.
What is the consequence of the boreal forest turning from a sink to a carbon source?
Boreal forests are at risk ofswitching from being a carbon sink to being acarbon sourcedue to effects of global warming on their ecosystem processes. This switch from sink to source is known as atipping point. This further increases thepositive feedback effects of global warming. Reduction in water availability that is caused by global warming is ahuge problem for boreal forests. Less snow fallsdue to increased temp, meaning thatless water is availablefrom snow melt water.
This leads todrought, reducing rates of photosynthesis in coniferous trees of boreal forests. Reduced photosynthesis meansreduced productivity, & over long periods can kill trees. Lack of water initially leads to a loss of green pigment & a process calledforest browning, where trees become brown. Eventuallytrees will die. Dead trees dry out &risk of forest fires increases. Loss of boreal forestreduces removal of CO2by photosynthesis, &increases release of CO2by combustion.
Combustion canrelease carbon that has been locked up for many yrsin living trees, dead needles on the ground, and within the soil itself; this is known aslegacy carbon combustion. This can tip forests from carbon sink to source, & can be irreversible.
Why does the melting of landfast ice and sea ice change polar haitat?
Many species rely on ice that forms at poles for their habitat. Sea iceforms when ocean freezes. Sea ice that is attached to land is known aslandfastice. Global warming means that there isless sea ice, & ice that does formbreaks apart & detaches from landearlier in yrthan previously, causing problems for breeding animals. Animals such as emperor penguin & polar bears use it for hunting, nesting sites and breeding grounds. Melting of landfast ice has many negative consequences.
How does climate change and landfast ice melting affect the emperor penguins and its breeding site?
- CC increase by GHG –> increase 2°C
- increase temp cause that delays in ice formation & early ice breakup can reduce rates of successful breeding & offspring & colony survival, even to point of local extinction
- Further, if we do lose that must sea ice, it could disrupt Antarctic food web, making emperors at risk of starvation & pop decline
- sea ice recession may also bring make new species to emperor breeding sites, resulting in more frequent predation & resources competition.
How does the melting of landfast ice and the subsequent loss of habitat affect the walruses in the Arctic?
- limiting amount of space available for walruses to congregate. Floating summer sea ice is also receding further north to where the water is too deep for animals to dive & feed. This forces them to desert ice & seek refuge ashore
- massive haulouts can be incredibly dangerous for walruses. Crowded animals are easily spoked; any sound or scent e.g. an airplane flying by, a human, or a whiff of a predator can cause a deadly stampede –> trample other walruses, especially young calves, which are susceptible to injury & death.
How does melting ice effect young of emperor penguins and walruses?
Emperor penguins,Aptenodytes forsteri:
- These birds breed onAntarcticsea ice, laying & incubating their eggs, and raising their young
- Early melting of sea ice is not giving them enough time to raise their young
Walruses,Odobenus rosmerus
- These mammals rely onArcticsea ice, where mothers can alternate periods of feeding their young & hunting for food in ocean nearby
- Early loss of ice means that nursing mothers need to care for their young further from water’s edge, leaving young without protection for longer periods when mothers hunt for food
How does water movement in the oceans effect the weather and climate?
Weather & climate are strongly influenced by water movement in oceans, which also play an essential role indistributing nutrients that support marine life. Ocean currents, driven by factors like wind, temp, & salinity gradients,redistribute heatacross Earth’s surface. Warm ocean currents carryheatfrom tropicstowards poles, moderating temps in coastal areas. E.g.Gulf Stream, a warm ocean current in Atlantic, means that Europe has a warmer climate than Canada, despite being at a similar latitude. Cold ocean currents transportcold waterfrom polar regionstowards tropics, resulting in cooler coastal temperatures & affecting marine ecosystems.
What is upwelling?
Upwellingoccurs when cold, nutrient-rich water rises tosurface, primarily driven bywindthat moves surface waters out of way, allowing deeper waters to rise up to replace them. Upwelling brings deep,nutrient-richwaters to surface, supporting abundant marine life & contributing to productivity of fisheries in coastal areas.
What implications could changes in oceanic currents have?
Changes in oceanic currents, such as alterations in current strength or shifts in their paths,can have significant implicationsfor regional & global climates, & formarine life. E.g. El Niño events, part of El Niño-Southern Oscillation (ENSO) cycle, have significant impacts on global weather patterns. El Niño events involve warming of central Pacific Ocean. Warm surface water preventsnutrient upwellingin waters off Central & South America,reducing primary production&flow of energythrough marine food chains in these regions. El Niño can also cause shifts in atmospheric circulation, leading todroughts, floods, & other extreme weather events.
What is upwelling and what doe it lead to?
-Warmer, less salty water is less dense and floats on top of denser, colder, saltier water.
- Diff layers mix as heat slowly seeps deeper into ocean by action of current, winds & tides. This = upwelling.
- With greater difference in densities between layers mixing becomes more difficult, resulting in oceans to become more stable.
What is nutrient upwelling?
- Nutrient upwelling is important, as it brings up nutrient rich water to surface where consumers can feed on them contributing to nutrient cycling.
- This is also the most active zone, bc sunlight can only penetrate this far into ocean.
- Carbon containing detritus & faeces sink to deep ocean by gravity.
What is the effect of climate change on species whose habitat is on mountains?
- CC is leading to warmer temp at each elevation.
- Species whose habitat is on mountains migrate upslope to find their optimal climate
What is tolerance limits?
Species existwithin tolerance limits, meaning that they can only survive in habitats where environmental conditions fall within theirrange (or zone) of tolerance. E.g. a marine species may only be able to survive in seawater that falls within certain temp limits
How has climate change effect tolerance limits?
CC is causingchanges to many local environmental factors; when this causes conditions of a habitat to changebeyond what a species can tolerate, species must eithermigrateto a new habitat orface extinction.
What migration has occurred due to climate change?
Migration may involve ashift inrangedistributiontowards poles, or to a higher altitude, to an area where temp are cooler. A range shift towards poles is described as apoleward shift. A range shift to a higher altitude is anupslope shift. Research has shown that distributions of many terrestrial organisms are currently shifting in latitude or elevation in response to changing climate. Range changes in elevation include species that move upwards in mountain ranges as warming conditions cause habitat ranges to shift higher. Species have zones of tolerance & so need to shift higher, to colder areas, as areas they live in warm. As conditions required by their niche change, so too does distribution of species. These shifting geographic distributions have been recorded in temp species & correlated to anthropogenic temp increases.
What is latitude and what is longitude?
What is the upslope range shift of mountain bird species in New Guinea?
In the tropics of Papa New Guinea species have been found to react more strongly to changes in temp than species from temp regions. Strong upslope shifts of bird species on two independent New Guinean mountains were found when comparing data from 1985 to data surveyed from 2017. Evidence gathered in mountains ofPapua New Guineaover a 50 yr period shows thatmany bird species have migrated to higher altitudesover this time period. (This isnot the case for all species; a few have stayed in the same place or moved downslope). Data were collected from 2 mountains in Papua New Guinea in 2012-13 – Mt Karimui and Karkar Island – & compared with historical data from 1960s.
On both mountains, bird species shifted their upper limits upslope significantly. On Mt Karimui by 113 metres & on Karkar Island by 152 metres. Upslope shifts also occurred at species’ lower limits on Mt Karimui by 95 metres.
What is the poleward range shift of North American tree species?
Combination of higher maximum temps in summertime & lengthened growing season has increased frequency of droughts.
Based on predictions & modelling, lower elevations & southern latitudes will no longer provide cool, wet habitats preferred by some species like sugar maple & hemlock, as well as other Northern American tree species. Various studies of North American tree species have shownrange contraction, i.e. ranges of these trees have shrunk, &northward spreadformany species. One study sampled 92 species in 43000 plots across eastern North America. Latitudinal differences were compared with 20th-century temp change. More than 1/2 of tree species showed indications that their ranges were shrinking at both their northern & southern habitat boundaries. Slightly more species showed their ranges were shifting just north, & only a few species indicated an increase at both north & south limits of their range.
What are coral reef and what are they made of?
Corals are colonies of small animals embedded in a calcium carbonate shell that they secrete. They form underwater structures, known as coral reefs, in warm, shallow water where sunlight penetrates. Specific microscopic photosynthetic algae (zooxanthellae) live sheltered & protected in cells of tropic corals.
Coral reefs are most diverse of ecosystems known &, although they cover less than 0.1% of surface of oceans, these reefs are home to about 25% of all marine species. Marine organisms take dissolved carbon in form of CO2 or HCO3- ions out of water & use some of it to make their carbonate shells. Organisms that build coral reefs are called coral polyps, & they combine Ca2+ from sea with carbon to form molecules of calcium carbonate (CaCO3). This molecule is basis of coral reef, & it is sturdy like rock. (Ca2+ + 2HCO3 – → CaCO3 + CO2 + H2O)
What coral bleaching?
Coral bleaching is whitening of corals that happens when a coral is stressed from a variety of factors, including poor water quality due to pollution, or more frequently warmer oceans, as a result of global warming due to increased carbon emissions.
What is ocean acidification?
Increased conc of CO2 in oceans has also led to another problem in addition to warmer waters – ocean acidification.
What is coral bleaching caused by?
Coral bleaching is caused by loss of symbiotic algae (zooxanthella) from tissue of corals as a result of pollution of increased water temp.
What causes ocean acidification?
- Linkages between buildup of atmospheric CO2 from burning fossil fuels & slowing of coral calcification due to ocean acidification.
- Atmospheric CO2 is absorbed by ocean & results in a decrease in carbonate ion conc, making carbonate ions unavailable to corals & other marine calcifies.
What are the consequences of ocean acidification?
- There are many consequences of ocean acidity, including dying of coral reefs, molluscs, crustaceans, as well as photo- & zooplankton such as foraminifers & coccolithophores, which are forming an essential component of ocean food chains.
- The acidity is also responsible for decrease in immunity of organism, increase in water noise & even cloud formation.
What is the relationship between polyp and coral?
Coral reefs are built from hardcalcium carbonatedeposits that are secreted by organisms calledcoral polyps. Note that not all corals build reefs; reefs are built by corals described asreef-building corals. These polyps live in asymbioticrelationship withalgae, in which the algae providecarbon compoundsthrough photosynthesis, & coral polyp providesshelter & protectionwithin its body.
What is the ecosystem in coral reefs like?
Coral reefs are some of mostdiverse ecosystemsin world; complex structures produced by reef-building corals provide habitats for many species, supportingcomplex food chains& providing suitable places tobreed & raise young. Around 25 % of world’s ocean fish species are dependent on coral reefs for survival.
What are threats to coral reefs?
Corals arehighly sensitiveto factors such aswater temperature&pH, & global warming can have highly damaging effects on life processes of coral polyps. Death of coral polypswill have a knock-on effect on all other species that rely on reef, disrupting food webs, reducing the availability ofniches& thereforereducing reef biodiversity. Many species will die off or migrate to other habitats. This leads toecosystem collapse.
What is the effect of rising ocean temperatures on coral?
- High water temps cause coral polyps toexpel their algae symbionts; this causes reefs to lose their bright colours & leads tocoral bleaching
- Bc polypsrely on algae for their carbon compounds, extended bleaching events can lead todeath of polyps
What is carbon sequestration?
Carbon sequestration = capture & storage of carbon through geological (peat formation) & biological (photosynthesis, biomass storage…) processes.
What are the three main approaches of increasing carbon sequestration?
- Afforestation
- Forest regeneration
- Restoration of peat forming wetland
What is afforestation?
This involves planting trees in areas where they currently do not exist. A number of countries have committed to achieving numerical goals for planting as an initiative to reverse desertification & to enhance carbon sequestration.
What is reforestation?
Forest regeneration or reforestation is restocking of forests that have been depleted through clearcutting. Usually this is achieved through planting seedlings in form of monocultures of trees which are commercially meaningful.
What is agroforestry?
Combines agriculture with forestry, allowing farmer to continue cropping while using trees for animal food, fuel & building timber. Trees protect, shade & fertilise soil, decreasing rates of decomposition & related rates of respiration & increasing photosynthesis. Such practices improve carbon sequestration in agricultural soils & above-ground biomass through a range of soil, crop & livestock management practices, & protect existing carbon in system by slowing decomposition of organic matter & reducing erosion.
What is peat?
- Peat is partially decayed organic matter that comes from unique waterlogged ecosystems such as bogs, muskegs & moors.
- It is commercially useful, as it services as a fuel, domestic heating, fertilizer & gardening soil.
- Globally, these wetlands form world’s largest carbon sinks.
What is peatland restoration?
Restoring peatlands requires the restoration of water levels, blocking drainage & re-establishing native species such as sphagnum moss.
What is example of peat restoration?
From 1640 onwards, large areas of wetland, such as East Anglian Fens in UK, were drained for farming, which degraded peat.
No longer waterlogged, peat shrank, decomposed & became eroded by wind, which increased flux of carbon dioxide into atmosphere. Restoring rich peatlands that were lost during agricultural development would enhance carbon sequestration of these wetland ecosystems.
Restoring these wetlands increases land carbon store & decreases atmospheric store.
Degraded & drained peatlands emit more than 2 gigatons of carbon dioxide annually.
Where is an example of carbon sequestration?
Hinewai reserve, New Zealand.
What is phenology?
Phenology is study of timing of seasonal activities in animals & plants. Word “phenology” is derived from Greek words “phainestain” (= to appear) & “logos” (= study).
What are the two main factors which determine the timing of biological events?
Photoperiodism & temp.
How does photoperiodism determine the timing of biological events?
- Day length is an important environmental signal which triggers developmental transitions like flowering in plants.
- Some crop plants only flower when day length is longer.
How does temperature determine the timing of biological events?
- Decreasing temp (together with short daylengths) in autumn are largely responsible for a cessation of growth in deciduous trees.
- Increasing temp in spring are for many plants a trigger for budburst (emergence of new leaves).
What are example of that are triggered by phenological events?
- change in leaf colour in autumn
- flowering in plants
- migration of birds
- ripening in fruits
- leaf bud formation
Why are phenological events triggered?
Changes in day length & associated light availability (photoperiod) & temp initiates or stops growth phases in most plants, resulting in bud burst or bud set.
How does urban areas affect the phenological events?
For a long time it has already been observed that phenological events such as budburst start differently when comparing rural with urban areas. Warmer temps in urbanised areas lead to different & extended seasonal growth periods. This also has an effect on synchronised interspecific relationships between animals & plants.
How has climate change affected phenological events?
CC candisrupt timings of biological events. Environmental cuesmay no longer function as they should, e.g. Tempmay be diff to previous years, Day length, known asphotoperiod, may not coincide with events that may have occurred in the past.
If events do not occur at right time, species will be leftwithout resourcesthat they need, &food chains will be disrupted. Trophic levels may be missing from food chain. This is known as a trophic mismatch.
How does climate change effect the synchronicity of phenological events?
CC can lead to a disruption of synchrony of phenological events.
Because migratory animals depend on food availability of plants & insects, changes to seasonal appearance of those causes a de-synchronisation, leaving animals with inadequate supplies of food.
What is the disrupted synchrony in the common reindeer?
- Reindeer (Rangifer tarandus, also known as caribou) has changed its migratory pattern in accordance with growing season of shrub, of which it mostly feeds on.
- Shrub arctic mouse ear (Cerastium arcticum) grows as a native plant in Greenland, northern Canada, parts of Norway & Siberia.
- Due to CC spring growth of this plant is advancing (i.e. coming earlier in year).
What is the disrupted synchrony in cuckoo?
Common Cuckoo is only brood parasite among breeding birds in Switzerland, leaving smaller songbirds to rear its young.
It overwinters more than 6000km away south of African Sahara.
Because warmer temp lead to an earlier start of spring, brood synchronisation becomes more difficult. Earlier availability of caterpillars as food source due to a shift in phenological events has caused local bird species to initiate rearing of young already – so when cuckoo arrives it might already too late.
What is the disrupted synchrony in the Alpine Pterigan?
Other synchronised events include change of plumage in bird species. Warmer temp in Alpine regions have lead to a decline of Alpine Ptarmigan.
A possible reason could be disrupted synchrony between loss of snow cover & camouflaging plumage, which results in it becoming an easier victim to predation.
What are the consequences of charged temperatures on insect life cycle?
- Increased number of generations
- Expansion of geographical range
- Outbreak of plant diseases transmitted by insects
- Increased overwintering survival
- Desynchronization of insects & their natural enemies
- Loss of synchrony with host plant.
What change in insect life cycle of spruce bark beetle?
- Beetles (the order Coleoptera) are most diverse & abundant group of insects on Earth.
- They inhabit every ecosystem except for the oceans.
While most beetles provide vital roles in ecosystem dynamics, some species have become pests. - One group, bark beetles, feed on tree plantations, damaging & killing trees.
- There are more than 2000 species of bark beetles.
- Great spruce bark beetle (Dendroctonus micans) is a non-native (alien) pest of spruce & pine trees in Europe.
- Eurasian Spruce bark beetle (Ips typographus) is one of most destructive forest insects in Europe, responsible for kiling of more than 50 million m³ of Norway spruce (Picea abies) since 1940s.
What are the 2 insect life cycle?
- Development of nymphs from eggs followed by instars (intermediate developmental stages) to adults E.g. locusts & grasshoppers
- Larvae are produced from eggs which then form a pupa (where developing organism is usually enclosed in a cocoon or protective covering). In pupa, organism undergoes internal changes (metamorphosis) where larval structures are replaced by those of adult. E.g. beetles
Why are bark beetles seen as pest?
Bark beetles bore into bark of tree and tunnel through to phloem where they lay eggs.
Emerging larvae feed on sap of phloem as well as tissue. New adults continue process, once they have pupated, making new holes through bark as they emerge. Phloem transports sucrose & other organic compounds around plant.
Larvae damage this tissue, which weakens tree & can lead to its death. Large areas of forest have been affected by outbreaks of bark beetle.
How does climate change affect an insects life cycle, especially the bark beetle?
Insects have short life cycles & are very mobile. Insect life cycles are very sensitive to temp.
Changes in temp due to CC results in changes to their rate of development & geographical distribution. Warming summer & winter temp have a major effect on beetle populations & increase chance of outbreaks across USA & Europe. Temp also lead to range expansion in some species (e.g. beetles spreading to new areas as temperatures warm). CC may increase risk of bark beetle outbreaks, particularly in old forests in northern Europe.
Research in Norway has shown that warmer winters also favour beetles & that, instead of one life cycle, two generations per yr could be formed (one in Spring & one in July/August), causing even more damage to trees.
What is natural selection? And how is it linked to climate change?
Natural selectionis driven byselection pressuresin environment. Selection pressures arefeatures of environment that limit the survival chancesof an individual, e.g. presence of a predator, a lack of food, or antibiotics killing bacteria. CC introducesnew selection pressures, so can drive evolution by natural selection.
What is the evolutionary consequences of climate change on the tawny owl?
Tawny owls show polymorphism, meaning that theirallelescan give rise to diffphenotypes, or morphs. E.g. some tawny owls aregreyin colour, while some arebrown. A decades-long Finnish study has shown anincrease in frequency of brown owlsin pop from around 30 % to around 50 %; this is thought be due to natural selection. In a snowy environment, pale grey owls are less visible, so are more successful & have a better chance of surviving & reproducing. It is not known whether decreased visibility is relevant to increased success in catching prey or increased success in avoiding predators, or both. Global warming and milder winters mean that there is less snow, &owls that are brown in colour have increased success; these brown owls are more likely to survive, reproduce & pass on their alleles for brown feathers.
