D2 & D3: The Vine Growth Cycle and The Growing Environment Flashcards
1
Q
Effect of Temperature: Under 10 degrees
A
ensures winter dormancy of vine
2
Q
Effect of Temperature: minus 20 degrees
A
can cause winter freeze and can damage the vine
3
Q
Effect of Temperature: above 10 degrees
A
Effect:
- stimulates budburst and a significant rise in temps can make ripening more uniform
- warm soils help budburst
Risk:
- cold temps and frost can be harmful and reduce yields
4
Q
Effect of Temperature: 18 - 33 degrees
A
- optimum temp for photosyn
- helps new shoots and leaves develop
- creates sugar for energy
5
Q
Effect of Temperature: above 17 degrees
A
- successful, uniform flowering
Risk:
- cold, damp conditions cause problems for flowering and fruit set
- impacts yield and quality of grapes and wine
6
Q
Effect of Temperature: optimum temp of 26 to 32 degrees
A
- successful, uniform fruit set
Risk:
- cold, damp conditions cause problems for flowering and fruit set
- impacts yield and quality of grapes and wine
7
Q
Effect of Temperature: above 25 degrees
A
- promote increased bud fruitfulness and impacts yields next year
8
Q
Effect of Temperature: Warm Temps
A
- sugar accumulation is faster as good conditions for photosyn
- increase grape transpiration as promotes movement of sugar into the grape
- malic acid degradation increased
9
Q
Effect of Temperature: above 21 degrees
A
- final months of ripening
- leads to rapid loss of acidity (anything below 15 degrees reduces acid loss so acidity levels in must is too high)
10
Q
Effect of Temperature: 15 degrees to 25 degrees
A
- anthocyanin synthesis optimum
- if it is too cool, it hinders breakdown of methoxypyrazines
11
Q
Effect of Temperature: Extreme heat
A
- causes photosynthesis to slow or stop
- water stress slows or stops photosyn due to shutting of stomata to prevent water loss and limits intake of CO2
12
Q
Effect of Temperature: Grape Varieties
A
- late ripening: need greater amount of heat through growing season to ripen sufficiently
- early ripening (e.g. Chardonnay, Pinot noir) need less heat in total and will ripen very early in warm climates
13
Q
Effects of Sunlight: why the vine needs sunshine
A
- needs sunlight for photosynthesis
- berry formation
- ripening
- needs at least 1/3 full sunshine but full sunshine is not a complete necessity
14
Q
Effect of Sunlight: Benefits (7)
A
- good in late spring/early summer for fruitfulness
- development of anthocyanins
- reduction of methoxypyrazines
- accumulation of tannins pre-veraison
- tannin polymerisation post-veraison
- development of aroma compounds
- lower acidity due to grape respiration
15
Q
Effects of Sunlight: Negatives (2)
A
- sunburn
- fog which can slow photosyn (not ideal but not very bad)
16
Q
Latitude: name 3 lower and 2 higher latitude regions
A
- lower: NSW, Mendoza, South Africa
- higher: northern France, Germany (closer to the poles)
17
Q
Latitude: closer to the equator
A
- more intense solar radiation
radiation travels through a smaller section of the atmosphere, hits the earths surface at a larger angle and therefore is more powerful
18
Q
Latitude: closer to the poles
A
- solar radiation has to travel through a larger section of the atmosphere to reach the surface
hits at a lower angle so it spreads at larger area
19
Q
Latitude
A
If all factors were considered equal, temps would be WARMER and sunshine more INTENSE at lower lats than at higher lats
Lower lat grapes are HIGH in sugar, LOWER in acidity, RIPER aromas, RIPER tannins and better COLOUR
20
Q
What does latitude determine?
A
- determines number of hours of solar radiation
- lower latitude = similar daylight hours (heat and sunlight) throughout all seasons- higher latitude = longer daylight hours in summer and shorter in winter - longer time for photosyn in growing seasons which is helpful in allowing vine to produce sugar for ripening grapes
21
Q
Latitude: grapes near the equator
A
- too hot
- water stressed
- sunburnt
22
Q
Latitude: grapes near the poles
A
- not warm enough
- lack of sugar in the grapes
23
Q
Altitude - how much does the temperature fall every 100m decrease in altitude?
A
- approx 0.6 degrees
EXAMPLE:
Salta: 3000m above sea level and grapes struggle to fully ripen
Burgundy/Loire: high latitude area. Plated at low altitudes so grapes can fully ripen
24
Q
Where is sunshine more intense - higher or lower altitudes?
A
- Higher
- solar radiation travels through less atmosphere
- UV radiation greater
- both factors promote anthocyanin and tannin synthesis
25
Benefits of higher altitude sites
- high diurnal range
| - air is thinner so less moisture and heat rapidly escapes
26
Benefits of lower altitude sites
- air absorbs moisture so heat is retained at night
27
On what side of the slope are sites planted in the Northern hemisphere?
- south-facing
Receives more solar radiation
28
On what side of the slope are sites planted on the Southern hemisphere?
- north-facing
Receives more solar radiation
29
Slopes and Aspect: Higher Latitudes
- solar radiation hits earth at low angle
- lowest in Spring and Autumn
- slope increases the angle which increases the intensity of heat and light exposure
- extra warmth and light during the spring and autumn extend viable growing season (e.g. in Grand Cru Alsace and Burgundy sites which are on SE facing slopes)
30
Slopes and Aspect: Warm Climates
- want to limit heat and light
- plant on slopes away from the sun
- get less alcohol and more acidity (e.g. in Stellenbosch white varieties are planted on south-facing slopes to help retain refreshing acidity)
31
Slopes and Aspect: East-facing slopes
benefits from morning sunshine which:
- heats up atmosphere when air and soil temps are at their lowest
- extends vine growth and grape ripening
- dew-covered canopy dries out quicker which prevents fungal disease
32
Slopes and Aspect: West-facing slopes
Afternoon sun:
- can get too hot
- risk of sunburn increases
- coastal areas can help alleviate this (e.g. Cali, Western Australia)
33
Additional benefits of vines planted on slopes
- shallower, poorer soil
- better drainage
- shelter from wind and rain
- protection from Frost
Negs:
- soil erosion
- can't use machinery
34
Benefit of planting close to body of water is...
- water heats up and cools down more slowly than dry land
| - over the year, larger bodies of water give cooler summers and milder winters
35
Proximity to water: day time benefits
- water and air above a body of water remain relatively cool
- lowers the average temperature
- air above land heats up quicker and rises so cool air from the water is drawn to land to replace it which gives cool, humid afternoon breezes
36
Proximity to water: night time benefits
- water retains warmth while land loses heat quickly
| - warmth from water keeps local area warmer
37
Examples of sites close to water
Finger Lakes: reduces severity of the winter freeze and protects against spring frosts
Carneros: Proximity to San Pablo Bay means that can grow early ripening varieties such as Pinot Noir and Chardonnay. Inland, can grow late ripening Cab due to warm afternoon breezes
38
Impact of Ocean Currents: Margaux vs Willamette Valley
- both at 45 degrees latitude
Margaux:
- late ripening Cab
- gulf stream benefits
- average growing season temp is 17.7 degrees
Willamette Valley:
- early ripening Pinot Noir
- cooled by cold California current
- average growing season temp is 15.9 degrees
39
wine regions shielded from ocean influences are...
warmer and drier (e.g. in western USA)
40
Reflections from water surfaces...
- can benefit from reflected radiation from water surface
- depends on angle at which solar radiation kits water
- advantageous in cool climates with limited sunshine
41
El Nino Southern Oscillation (ENSO)
- climate cycle in Pacific Ocean and has a significant impact on weather pattern
- El Nino
- La Nina
42
El Nino
- warm water in western Pacific ocean moves eastwards along the Equator towards the Caribbean
- Eastern PO becomes warmer than average causing high rainfall and risk of hurricanes to South Am and Cali
NEGATIVES
- disrupt pollination and fruit set
- excessive water so increases vegetative growth
- hinder ripening
POSITIVE
- warmer than average temps for PNW
43
What are the impacts of El Nino on Australia?
- warmer temps and drought
| - causes extreme vine stress and damage
44
How often does El Nino occur?
- every 3 to 7 years but likely to be more frequent due to climate change
45
La Nina
- causes Eastern PO to be cooler than average
- causes cooler/wetter conditions in the PNW
- warmer and drier in California and South America
- causes wetter/cooler conditions in Australia
46
Winds
- can be warming or cooling
- near a body of water helps bring in cool breezes during the day, moderating the diurnal range
- reduces humid/stagnant air in canopy - reduces risk of fungal disease
47
Winds: valleys facing coast/low lands
- can feel winds in land
- e.g. Petaluma Gap
- can also funnel wind
48
Wind: hot land masses
- brings in warm air to heat vineyard
| - e.g. Zonda in Mendoza
49
Winds: evapotranspiration
- wind increases rate of evapotranspiration
- water needs are much higher than non-windy areas
- can lead to water stress
50
What is the impact of strong winds?
- damage to vines and trellising
- lower yields
- higher equipment and labour costs
- can plant trees as wind breaks but need to be careful that they don't compete with vines for nutrients or water
51
Soil: warm soils
- encourages breakdown of starch in roots = stimulates budburst and shoot growth
- encourages root growth to absorb more water and nutrients
RISK:
- early budburst risks spring frosts harming young buds
- main risk in well drained souls
- good for cool climates so get early-budburst and longer ripening season
52
Soil: colour
Light Soils
- e.g. chalk
- reflects energy from solar radiation
- good for lower part of canopy which doesn't get as much sunlight so increases photosyn and ripening
Dark Soils
- e.g. volcanic
- absorbs more energy and re-radiate it when temps are cooler (e.g. at night)
- allows development of colour and degradation of acid to continue at night
Stony
- good at absorbing heat and releasing at night
53
Mist
- tiny drops of water collecting in air just above area of ground or water
- formed when warm air rapidly cooled, causing water vapour to condense
*all can increase risk of fungal disease or noble rot
54
Fog
- dense mist
- mostly in the morning
- Leyda, Napa, Sonoma, Sauternes
*all can increase risk of fungal disease or noble rot
55
Clouds
- form higher in the sky
- reduces sunlight and therefore photosyn
- can lower temps
- can slow down sugar accumulation and acid degradation which can be beneficial in warm regions
*all can increase risk of fungal disease or noble rot
56
Diurnal Range
- average difference between day and night temps
- continental climates or high altitudes have higher diurnal ranges
- regions near body of water have lower diurnal range
57
Diurnal Range: Hot Climates
- e.g. Mendoza, Ribero del Duero
| - high DR seen as favourable to slow respiration of malic acid and for formation of anthocyanins
58
Diurnal Range: Cool/Mod climates
- e.g. Mosel, Mornington Peninsula
- low DR favourable so night time temps still allow ripening to continue which are needed for grapes to ripen sufficiently
59
Diurnal Range: What impact does it have on aroma compounds?
- warmer nights = greater breakdown of methoxypyrazines
| - cooler nights = greater retention of other compounds
60
Give an example of where cold night temps (under 15 degrees) are beneficial in cool climates?
Wachau
61
What are the minimum water requirements for vines in a cool and warm climate?
Cool climates: min 500mm per year
Warm climates: min 750mm per year
62
What does a vine need water for?
- turgidity
- photosyn
- regulating temperatures
- solvent for nutrients in soil
- medium for vines biochemical and physiological mechanisms to take place
63
Define Transpiration
- water vapour diffuses out of stomata on underside of leaves
- causes water to be pulled up from soil, roots and above ground parts of vine
64
What is the role of the stomata?
- allows exchange of water vapour out of the vine
- lets CO2 and O2 diffuse in and out of the leaves
- stomata kept open all day with sufficient water
- will close stomata if lack of water (even partially)
- conserves water
- reduces/stops photosyn (lack of CO2 entering leaves) so growth is stunted and ripening slows
65
What is the impact of water stress?
- leaf loss
- vine death
- may need to irrigate in some regions
EXAMPLE:
- Argentina, Cali, SA, Australia
66
What is the impact of excessive water?
- excessive vegetative growth which competes with vine sugars and delays/compromises grape ripening
- shading of bunches due to excessive canopy which impacts formation of anthocyanins, tannins, aromas, tannin polymerisation and higher levels of methoxypyrazines
- poor ventilation and therefore increased risk of fungal disease
- dilution of sugars; can cause grapes to split which can cause botrytis
67
What is the impact of water deficiency?
- grapes shrivel
- grapes don't reach ripeness
- some mild water stress before veraison is helpful as it inhibits vegetative growth
68
Soils: damp soil
- cold
| - can delay budburst which can shorten the growing season
69
Impact of Hail
- causes major damage to green part of vines
- lowers the yield
- reduces quality of remaining fruit
70
Impact of Rainfall
- has negative impact on pollination and fruit set and can lead to uneven ripening and lower yields
- causes humid environment in canopy so increased risk of disease (powdery mildew and botrytis)
- low humidity increases evapotranspiration and water stress
71
Impact of bodies of water
- moderate diurnal range and seasonal temperatures
- increases and decreases average temperature in the growing season
- encourages breezes which helps reduce the risk of frost
- increases humidity and therefore the risk of fungal disease
72
Natural factors affecting water availability: rainfall
- amount and timing each year is v important
- moderated by water-holding capacity and depth of the soil
- may need irrigation if not sufficient enough rainfall
- caused by water vapour condensing and precipitating
- can fall as rain, snow or hail
- all natural sources of water
73
Natural factors affecting water availability: rainfall and topography
- mountain ranges force winds of warm moist air upwards over high altitudes which causes vapor to condense and precipitate
- means regions on one side of mountain experience greater rainfall and the other side is sheltered and very dry (RAIN SHADOW)
74
Give an example of the impact of a rain shadow
West of Cascade Mountains - Puget Sound AVA
- cooler and wetter
East of Cascade Mountains - Columbia Valley
- warmer and drier so need to irrigate for vines to survive
75
Natural factors affecting water availability: Soil
- significant influence on availability of water for vines roots
- available water dependent on:
1. how easily water drains
2. water-holding properties
3. soil depth
76
Given an example of the impact of soil and its water retaining properties
Hawkes Bay, NZ
- 800mm rainfall PA
- extremely free draining GRAVEL soils
- irrigation sometimes required
Jerez
- 650mm rainfall PA
- ALBARIZA soils (clay) - good water retention
- releases water slowly to vines
- crust forms on the top to reduce evaporation
77
What is the impact of water-logged soils?
- can be harmful to roots and the vine as it reduces the amount of oxygen available, therefore slowing growth and killing the vine
78
Natural factors affecting water availability: Topography
- greater surface run off on slopes so therefore less penetration of water in the soil and less water available for the roots
- good in areas with high rainfall
- does increase the risk of soil erosion and leaching of nutrients
- soils are quite thin which therefore limits area over which vines can get water and nutrients
79
Evapotranspiration Rate
- amount of transpiration from the vine combined with evaporation of water from soils surface = rate at which water is no longer available
80
What does the Evapotranspiration rate depend on?
- temperature
- humidity
- wind
e.g. dry, hot, windy weather = faster evapotranspiration rate (Mendoza, Patagonia)
With a higher rate need much more water and therefore may need to irrigate
81
What are nutrients important for?
- healthy vine growth
| - influence yield and grape composition
82
What level of nutrients does a vine need?
- low levels of nutrients
| - nutrients can be depleted by viticulture so important to monitor for deficiencies
83
What are the five key nutrients a vine might need?
- nitrogen
- potassium
- phosphorous
- calcium
- magnesium
84
Nutrients: NITROGEN
- essential
- restricted quantities produce high quality grapes
- impacts vine vigour and grape quality
- component of proteins and chlorophyll which are needed for photosynthesis
TOO MUCH:
- excessive vegetative growth (sugars going to shoots and leaves rather than grapes)
- shading of fruits and buds
- poor ventilation
TOO LITTLE:
- reduced vigour
- yellowing of vine leaves
- issue for fermentation
85
Nutrients: POTASSIUM
- essential
- regulates flow of water in vine
TOO MUCH:
- issue in uptake of magnesium
- reduced yield and poor ripening
- high potassium levels in grapes are linked to high pH in wine
TOO LITTLE:
- low sugar accumulation
- reduced yields
- poor vine growth
86
Nutrients: PHOSPHORUS
- important for photosynthesis
- only need a small amount
- normally enough present in soil naturally
TOO LITTLE:
- poorly developed root system
- diminished ability to take up water and nutrients
- reduced vine growth and lower yields
87
Nutrients: CALCIUM
- important for structure of plant cells
- important for photosynthesis
TOO LITTLE:
- rare
- negative impact on fruit set
88
Nutrients: MAGNESIUM
- found in chlorophyll
- key role in photosynthesis
TOO LITTLE:
- reduced grape yields
- poor ripening
89
What impact does 'soil' have on nutrient availability?
- soil pH has a key influence
| - different nutrients become more or less available depending on the pH
90
What is Chlorosis and what does it cause?
- lack of iron in soils with high pH
- turns leaves yellow
- photosynthesis stops
- grape ripening and yields are negatively affected
91
What are 'organic nutrient compounds' and what are they good for?
- need to be converted into organic compounds
- bacteria/fungi/earthworms/organisms living in soil do this by feeding on it and converting it into available forms
- called 'mineralisation'
- need good soil life and ecosystem
92
Describe what each soil type is life for holding nutrients
- clay soils: good at holding nutrients
- sandy soils: poor at holding nutrients
humus can increase a soils ability to hold nutrients
93
How does vineyard position (on slopes or valley floor) impact its soil fertility?
- Slopes: thinner and less fertile
| - Valley floor: very fertile
94
What three things is soil typically made up of?
- geological sediment (comes from weathering of bedrock)
- organic remains (humus)
- pores between sediment containing water and air
95
What is vineyard soil made up of?
- different layers formed at different periods
| - all have different textures, characteristics and structures
96
What is the role of soil in the vineyard?
- supports vines roots and is the medium from which vines take up water and nutrients
- key habitat for vineyard ecosystem
*limited/no scientific backing on link between soil and flavours/aromas in wine
97
What are the two most important physical elements of soil?
- texture
| - structure
98
Describe what is meant by soil 'texture' and what are the three main textures and two sub textures
- describes proportions of mineral particles of sand, silt and clay
CLAY
- finely textured
- small particles
- large surface area compared to volume
- effective at holding water and nutrients
SAND
- large particles
- small surface area compared to volume
- limited capacity to hold water and nutrients
- loose texture so easy for roots to grow
SILT
- intermediate size
- in between sand and clay
LOAM
- moderate proportions of clay, silt and sand
ROCK FRAGMENTS
- e.g. gravel and pebbles
- larger particles improve water drainage
- low water/nutrient retention capacity
99
Describe what is meant by soil 'structure' and what does this mean for three different types of soil structure
- describes how mineral particles in soil form aggregates (crumbs)
- size, shape and stability of crumbs determine:
- water drainage
- root growth
- workability of soil
HIGH CLAY CONTENT
- sticky
- form clay agregates which are difficult to penetrate and challenging to cultivate
- roots can only get down through cracks
SAND/GRAVEL/PEBBLES
- loose structure
- need clay to help bind
HUMUS
- formed by partial decomposition of plant material by soil microbes and earthworms
- spongey texture
- large surface area
- able to absorb water and nutrients
- binds soils
- helps with retention of water and nutrients
100
What does soil stability depend on and describe it for different soil types?
- texture and structure, combined with how far roots can penetrate
Sandy/stony soils
- poor water and nutrient retention capacity
- good for roots to be able to grow deeply
- large area for vine to get water
Free draining soils
- good for draining with excessive rainfall
- e.g. gravel soils in Haut-Medoc
- waterlogged soils = reduced growth and vine death
101
What is the impact of excessive water in soil?
- can displace oxygen which is essential for respiration of roots and organisms
102
Define what is meant by 'climate'
- annual pattern of temperature, sunlight, rainfall, humidity and wine
- averaged over approximately 30 years
- doesn't change yearly - can alter over decades
103
Temperature, sun and water influence...
...growing and ripening of grapes, plus style and quality of wine from a region
104
What do 'climatic bands' do?
help compare different global vineyards and different styles of wine
105
What do most climate classifications focus on?
- temperature
- some focus on rainfall as well
- don't take all natural and human factors into account
106
What are the six different climate classifications in use?
- Growing Degree Days (GDD)
- Hughlin Index
- Mean Temperature of Warmest Month (MJT)
- Growing Season Temperature (GST)
- Koppen's Classification
- WSET
107
CLIMATE CLASSIFICATION
Growing Degree Days (GDD)
- Amerine and Winkler 1944
- heat summation during growing season
- intended for use un Californian vineyards
CELCIUS
- subtract 10 (temp below which vines can't grow) from average mean temp of month in growing season
- multiply by number of days in month
- do this for every month in a growing season
- add totals together to get GDD
FARENHEIT
- exactly the same but subtract 50 from av mean temp of month in growing season
GDDs are grouped into 5 ranges
EXAMPLE: Winkler Zone 1 - cool
Winkler Zone 5 - very hot
Recently updated to add new upper and lower bands
108
CLIMATE CLASSIFICATION
Hughlin Index
- Hughlin 1978
- similar formula to GDD but calculation takes into consideration mean maximum temp AND increased day temps at higher latitudes
- split into ranges and grapes are mapped into each range
- widely used in Europe
109
CLIMATE CLASSIFICATION
Mean Temperature of Warmest Months (MJT)
- Smart and Dry (1980)
- Mean temp of July/Jan
- also includes: continentality
humidity
hours of sunshine
- temperature divided into six bands, ranging from cold to very hot
110
CLIMATE CLASSIFICATION
Growing Season Temperature (GST)
- mean temperature of growing season
- grouped into climatic bands from cool to hot
- close to GDD but easier to calculate
111
CLIMATE CLASSIFICATION
Koppen's Classification
- 1900
- considers temperature and rainfall
- apply to wine regions in temperate zones (not vineyards in tropics)
MARITIME
- low annual difference between summer and winter
- even rainfall throughout the year
- e.g. Bordeaux
MEDITERRANEAN
- low annual difference between summer and winter
- annual rainfall in winter months
- dry summer
- e.g. Napa Valley, Coonawarra
CONTINENTAL
- extreme difference between summer and winter
- short summers and cold winters
- rapidly changing temps in spring and autumn
- e.g. Burgundy, Alsace
112
CLIMATE CLASSIFICATION
WSET
COOL
- average GST of 16.5 or below
MODERATE
- average GST of 16.5 - 18.5
WARM
- average GST of 18.5 to 21
HOT
- average GST over 21
113
Describe the impact of temperature and rainfall timings on vine growth, grape ripening and wine styles and quality
- extreme winters: winter freeze
- increase in spring temps: even budburst
- warm summers: good sugar ripeness; can lack acidity; high alcohol
- cool growing season: too low sugar; too high acid
114
What is 'continentality'?
- measure of difference between annual mean temps of the hottest and coldest months
- large bodies of water help moderate this
- inland regions (or away/protected from oceans) have high continentality and are classed as 'continental'
- regions near coast/near body of water have low continentality and are categorised as 'maritime' or 'mediterranean'
115
What is 'weather'?
- a region's weather is ANNUAL VARIATION that happens relative to climatic average
- some see more variation than others
EXAMPLE
- Central Valley, California: predictable, hot and dry from one year to the next
- Bordeaux: 2007 August - cool, cloudy, wet
2003 August - hot, near drought
116
What impact does fluctuating weather patterns have?
* **causes vintage variation
- influences sugar, acid, tannins, aromas etc
- impacts winemaking choices
- welcomed for some wines
- not good for high-vol, cheap wines, or mass-produced sparkling
117
What impact does weather have on yields?
- rain = more fungal disease so less yield
- frost = reduction in yield
- larger yields can be difficult for wineries to manage if they don't have the capacity
- less wine = less amount to sell so impact on cash flow and customer relations
118
What is the impact of climate change on grape growing?
- wine production likely to be strongly affected
- rise in temperatures = greater evapotranspiration and therefore water stress
- change in geographical distribution of rainfall
- weather variability
- frequency of extreme weather events
119
What is the impact of rising temperatures as a result of climate change?
- vine cycle is faster
- budburst earlier in spring
- sped up rate of sugar accumulation
- reduction of acidity
- doesn't speed up tannin or aroma development therefore grapes are picked with higher levels of sugar which results in higher alcohol and lower acidity in final wine
Some regions may become too warm for certain varieties and have to switch to late ripening varieties
120
What might be the impact on aromas of climate change?
- grapes might not have same profile as now
| - e.g. NR Syrah - known for black pepper aromas which might no longer develop
121
What might be the impact on water stress as as result of climate change?
- good for some regions which have high rainfall as it reduces disease and promotes mild water stress
Overall risk is that is promotes extreme water stress in very dry regions so photosynthesis could stop and vines could lose leaves
areas such as South Africa and California are seeing extreme drought and excessive temperatures so may see some sites abandoned in next 50 to 100 years
122
Name some extreme/erratic weather as a result of climate change
- storms
- hurricanes
- floods
- unseasonal frost
- heatwaves
