Climate Lecture Flashcards
what is the difference between weather and climate?
the climate is measured over a min. 30-year average
what are the three main changes as a result of global warming (across the world, not relating to wine or vineyards)
oceans are warming
sea level is rising
arctic sea ice volume is declining
what is one of the largest issues facing viticulture due to climate change?
not getting rain when we used or expect to get it
how is rainfall in Australia changing?
we are getting less rain, but patterns are also changing.
Eg, we get massive amounts in one go, as opposed to nice even flow of rain
what are the external forcing mechanisms of climate change
- land clearing
- pollution
what are the internal variability causes of climate change
varying weather patterns sun flares ocean currents - el Nino and el Nina volcanic eruptions smoke in the atmosphere
without the greenhouse effect, the earth’s surface temp would be…?
what is it now?
-18
it is now 15 or 17
doubling CO2 will lead to what temp increase across the globe?
5-6 degree
what is a greenhouse gas?
a molecule with more than two atoms in its structure
what is an important semantic distinction to make when referring to the greenhouse effect?
it is the ‘enhanced’ greenhouse effect
what is the ‘enhanced’ greenhouse effect
increasing levels of CO 2 and other greenhouse gases increase the amount of heat that is being retained between the earth and ozone layer, thus the earth’s surface heats up
in the last 20 years, how many of the warmest years ever recorded have occurred?
17
sustained temps above ____ are a big issue for viticulture
35 degrees
what are the expected temp increase between now and:
2030:
2070:
2030: 0.7-1.2 degrees
2070: 2.3-3.5 degrees
what is the expected rainfall decreases between now and:
2030:
2070:
2030: 4%
2070: 12-13%
what is the expected vineyard water requirement increase between now and:
2030:
2070:
2030: 7%
2070: 20-25%
what is a technique used to be more efficient with water use in irrigation?
watering only half the vine
what temp frost could destroy an entire vineyard?
what temp will do damage but perhaps to only certain areas?
-5
-1
vines won’t die, it will just be the shoots
when is frost the largest concern for viticulturalists?
spring - budburst
what is the expected CO2 range as global warming continues?
450 parts per million
how far is the “belt” that is suitable for growing vines around the world expected to move by 2050?
150-300km towards poles
NH towards the north, SH towards the south
what is the growing season average temp isotherm?
12-22 degrees
what is the growing season in months for:
Northern hemisphere
southern hemisphere
NH: April - October
SH: October to April
what are the varying things that can affect wine quality due to climate change
- elevated CO2
- accelerated phenology
- extreme heat
- frost
- changed pest and disease pressures
- water availability
how does extreme heat affect viticulture
turns all the berries to raisins
how can climate change impact pests and disease management in vineyards?
- increased humidity may introduce new pests that we do not currently understand, therefore cannot ward against
what is the phenology of the vines/plants?
the yearly cycle
30/40 years ago, when did we start/finish harvesting?
end of Jan - early April
how is changing phenology affecting the industry?
all grape varieties are now reaching optimum ripeness within one to two weeks of each other, when it used to be 6-8 weeks… means more grapes are coming in at the same time which puts pressure on the winery in regards to space, fermenting utensils, storage etc
what effect are hotter temps having on ripening? what does this mean?
faster ripening, this means though that less development of flavour compared to what we see with a slow ripening
also a decrease in acids
- don’t get an accumulation of tannins
what do vines use to grow and ripen fruit (berries/grapes)
photosynthesis - converts sunlight to sugar
what is the optimum temp range where vines are most efficient with photosynthesis? outside of this temp, what does the vine do?
15-30 degrees.
the vine shuts down
what causes vine stress?
- lack of soil moisture
- extreme temps over 35 degrees
- diseases and pests
- frost at critical times - budburst and fruit set
what are the negative outcomes of vine stress?
- change in quality - flavours, acids and tannins
- uneven ripeness
- loss of crop
- change in ripening time
name how heatwaves at different times of the cycles can impact grapes
heatwave at flowering: all flowers die and you don’t get fruit set… results in only a third or less of fruit you expected
Heatwave at veraison: can delay veraison and get uneven ripening.. some of the vineyards will be ripe and some won’t
Heatwave at harvest: grapes “raisin off” and you lose half your yield
what is smoke taint? when is it most threatening?
when smoke affects the grapes/vines
makes wine taste like ashtray
smoke at specific times, eg after veraison, closer to harvest is when it can do the most damage
how can extreme rain affect vineyards?
- fungal and mildew diseases can evolve as a result
- erosion - can lose a huge amount of soil
what are the extreme events that can affect a vineyard
heatwaves fire danger extreme rain frost pests and diseases
why is frost as a risk topical at the moment?
because of the changing phenology of the vineyard, bud burst is occurring earlier (into the winter months where there are frosts)
what conditions enable a frost to happen?
lower rainfall
drier soils
fewer clouds
lower dew points
what are the potential impacts of more hot days and warm spells?
- shrivelled grapes
- stalled development
- sunburn of grapes
- leaf damage - issues with photosynthesis to provide flavour and also act as shade to keep canopy cool
- vineyard logistics - can’t send people out in hot days
positive: less frost for some regions
how will increased drought affect vineyards?
- more expensive for winemakers as have to pay for water
- however, do not have to worry about diseases as much
what are the effects if trunks of the vines burn?
they may reshoot a year or even two years later, but after that, they are likely to die as they have sustained damage to the inside of the vine
what are the potential impacts of severe rainfall?
- lower-lying areas can be affected if they are in water which can lead to increase disease pressure (fungal and powdery mildew)
- berry splitting - if the vine is sitting in water, it will take on this water and direct it to the grapes
- difficulty in obtaining fungicide because everyone wants them after a severe downpour
- transport logistics - harvesters and tractors
what pest and disease risks are associated with changing climate?
- rainfall increase chances of mould and mildew
- a warmer climate may bring new pests south
- increased chance of plague type outbreaks eg, ladybugs on vines getting caught up in the harvesting process then also the fermenting process drastically affects the taste of wine
what is the holding period of putting out insecticide before harvesting?
2 weeks
why did Australia’s wine governing body allow water to be added to wine for the first time practically ever?
because climate change is affecting grape maturity which means more sugars are ending up in the wine.
This means that when fermented, there will be higher alcohol content which makes for bad wine when alcohol is too much, hence the water was able to be added to dilute it
what are the effects of elevated co2?
- increases crop growth by 20%
- decreases water loss
- increases canopy temp
pre-1998, what was the average date that pinot noir grapes would reach 21 brix (11 or so baume)?
what is it post 1998 ?
pre: 10th april
post: 13th march
for every degree of warming that we get, how many days of earlier ripening will we get?
10 days
between 1940 and now in Goulburn valley (where dookie is), how many days earlier is ripening/harvesting happening?
what are the non climate change impact influencing this?
23 days earlier
16 days are due to non climate change reasons
- vineyard management… we are managing and purposefully making vines ripen earlier
if vines increase their ability to accumulate carbon, what will result?
t or false, management practices have been encouraging this?
faster ripening.
True
what tactics can be employed to reverse early ripening, slow ripening?
- watering close to harvest delays the harvest (baume can go backwards)
- pruning later in the season and in different ways eg, cutting back further
- when and how we fertilize
regarding ripening, what does less fluctuation in temp produce?
more complex flavours
what is a maritime influence of grapevines
where vines grow near a large body of water (could be lake or ocean etc)
results in less fluctuation in temp between day and night
where are pinot noir varieties climatically suited at the moment?
northern Tasmania and Mornington peninsula
what are flavour profiles of:
cool climate shiraz:
hot climate shiraz:
cool climate shiraz: spicy/peppery
hot climate shiraz: jammy/fruity
in the southern hemisphere between October and April, what temp ranges classify cool intermediate warm hot climates?
cool: 13-15 degrees
intermediate: 15-17
warm: 17-19
hot: 19-24
specify what climate each of the below grapevine varieties prefer riesling: pinot: chardonnay: Sav blanc: semillon: merlot: shiraz: cab sav:
riesling: cool/intermediate
pinot: Little bit of cool/intermediate
chardonnay: Little bit of cool/mainly intermediate
Sav Blanc: intermediate
Semillon: intermediate/little bit of warm
merlot: intermediate - warm
shiraz: intermediate - warm
cab sav: a bit of intermediate, warm and a bit of hot
describe
Macro-climate
Meso -
Micro -
Macroclimate - region as a whole
Meso - climate of the vineyard or the site
Micro - the vine itself
describe the below effects and their impacts on climate
Latitude -
Altitude -
Maritime effect -
Latitude - higher you go in the southern hemisphere, the warmer it gets
Altitude - higher = cooler
Maritime effect - less variation between day and night
Methoxypyrazine is a volatile compound.
what are its flavour profiles and which regions of sav Blancs have a lot of it? how much do these wine typically have?
grassy, green capsicum, leafy
NZ Marlborough
10-30 ng/L
rotundone is another volatile compound
- what is its flavour profile?
- what type of shiraz is it common in?
- at what point is it detectable in red wine by humans?
- peppery
- cool climate shiraz
- 16 ng/L
what is ng/L
nanograms per litre
what per cent of the population cannot smell rotundone?
20%
