North Douglas Herald
April 2024
Wine Growers vs Climate Change
Continued from Page 1
vineyards may be useless.
Grapes have a complex reaction to heat.
“You need a degree of heat to get through the
ripening phase, get sugar accumulation, and get
the ideal amount of development of some of these
secondary compounds like anthocyanins and
tannins—all the things that make wine exciting
and interesting and have good mouthfeel,” notes
UC Davis viticulturist and ecologist Elisabeth
Forrestel, who wasn’t involved in the new paper
“Grapes suffer when temperatures exceed certain
levels.”
Fruit damaged by extreme heat waves is
less tasty. Sugars concentrate when grapes are
desiccated at higher temperatures. Sugar boosts
alcohol. Wine will get drunk faster due to climate
change. Gambetta says, “Depending on who you
are, where you come from, this can be bad. If a
region has always defined a style, that will change
the wine.”
High temperatures break down the volatile
compounds that becomes gas, or the wine’s
“nose”. “The profiles tend to get pushed to what
sensory scientists would call the ‘cooked’ side of
the spectrum: “jammy”, or like cooked fruit,” adds
Gambetta. “This may be good. Some prefer these
wines, which is fine. So it all depends on regional
identity.”
For winemaking, warm days and moderate
nights heat and cool grapes. Climate change is
disrupting that cycle. “It’s actually the nights that
are warming faster than the days,” says Forrestel.
No late-night fruit chilling. Daytime temperatures
above optimum, destroys numerous essential
chemicals.
Even without drought, higher temperatures
dehydrate plants. Winemakers receive less
grape juice due to lower yield. Drought lowers
output. Gambetta says, “Over the past 100 years,
Bordeaux, where I work, has had pretty steady
rainfall.” Rising temperatures reduce agricultural
water consumption.
Vineyards can be over-watered. Supercharged
rainstorms and worldwide floods result from
warming air holding more moisture. Grape roots
lose oxygen if precipitation remains in a vineyard.
Even with 14 inches of rain a year,
Mediterranean grapes like grenache can produce
great yields and wines without irrigation. A
vine may withstand a drought by defoliating or
producing less. Because it won’t hurt the vine, it
can recuperate after rain.
Wine-growing regions are suffering from
more frequent and severe droughts due to climate
change. “In 2022, which was outrageous by all
definitions in Europe—in Portugal, and parts
of Spain—they had seriously stunted vines,
defoliated vines,” Gambetta adds. “Then you can
get into this dangerous territory where you have not
only catastrophic effects that season, but carryover
effects to subsequent seasons.”
The review paper goes on to say “We
estimate a substantial risk of unsuitability (ranging
from moderate to high) for 49-70% of existing
wine regions, contingent on the degree of global
warming.”
With a 2°C global warming increase over
pre-industrial levels, Southern California may no
longer be suitable for wine production. Increasing
temperatures by 2–4 degrees Celsius would place
the region at “high risk of unsuitability.” The West
Coast of the US produces 10% of the world’s wine
and most of North America’s, so this is a big deal
to the California wine industry.
“Overall, the net suitable area for wine
production in California could decline by up to
50% by the end of the 21st century,” experts said.
“Similar risks exist for Mexico, the southwestern
United States and those regions of the east coast
south of New Jersey.” Much of southern Europe
has seen these same shifts and indicators.
Climate change could also spread insects
and illnesses that affect farming and public health.
Downy mildew and other grapevine issues are less
frequent in drier regions, but outbreaks will emerge
early and spread faster.
Adaptation to climate change is “mandatory,”
say the scientists. Winemakers must choose grapes
that thrive in diverse and changing climates and
seasons. It’s vital to wine quality and global
availability.
Scientific studies reveal that environmental
factors affect acidity, alcohol, and pH. Wines
have increasing alcohol and pH levels, but lower
acidity, making the wine’s microbiology more
unstable. The study suggests an “increased risk
of microbiological spoilage”, leading to “overripe
and/or cooked fruit aroma”.
Scientists say worldwide climate change
plans are insufficient. In 2024, we already have
record-breaking temperatures and a range of
meteorological extremes, from out-of-season
warmth to massive blizzards. The hottest year ever
was 2023, and 2024 is barely started.
The global average temperature is 1.35
degrees Celsius greater than pre-industrialization
averages. This does not mean we have exceeded
the 2-degree Celsius barrier that scientists say
might have dire repercussions, but we are close.
The worldwide average was 2 degrees Celsius
above the pre-industrial average for the first 12-
month period in a row, so it’s on it’s way.
“One thing is certain,” the researchers
concluded, “climate change will drive major
changes in global wine production in the near
future.” Being able to adapt to these adjustments
is going to be vital.
Vineyards may customize irrigation. This
is more expensive and may strain local freshwater
supplies: Drought requires more water for
everyone. Europe’s heat waves will still threaten
all farming.
Warming may move vineyards north.
According to the latest analysis, northern Europe
and North America may need 80 to 200 percent
more winemaking land, depending on climate.
Winemaking is booming in Oregon, Washington,
and southern UK.
Climate change will interrupt activities in
such places too. Days-long heat waves topping 110
degrees Fahrenheit have hit the Pacific Northwest.
Huge West Coast wildfires have already scorched
vineyards.
Supply chain difficulties and climate change
are rising wine prices. The bark of cork trees is
gathered often to manufacture corks. Teams cannot
safely remove bark from drought-stricken trees.
Bottle glass prices are rising for wine as well.
Scientists examine plant cooling strategies
to help vineyards adapt. Crops under grapes cool
the fruit. A vineyard floor’s exposed soils heat up
and reflect heat back into the canopy, according
to Forrestel. “I think we’re just beginning to
understand the impacts of some of these truly
extreme events because they’re recent and
becoming more frequent.”
Winegrowers may amend plants but
not weather. Heat wave water loss is reduced
by reducing leaf biomass, while “canopy
management” shades berries with leftover leaves.
In several places, winegrowers are testing drought-
and heat-tolerant grape varieties. Adding deeper
root systems helps plants get soil water.
Gambetta says, “Changing the variety is
a huge, huge lever, because varieties have huge
variation in how they behave.” Much easier said
than done. Bordeaux has a long tradition of great
wines and a stable climate. New variants have
been extensively studied. “Has there been an
uptake? Growers alter? Gambetta replies no, they
don’t. “They can’t just make a new wine and say,
‘Hey, listen, here’s my new wine,’ and expect it
to sell well. Since these identities underpin whole
regions.”
The grape paradox. Winemakers aim for
the consistency their fans demand. Since they’re
hardy, grapes may grow anywhere, from Bordeaux
to Napa to Chile and South Africa. “It just is a plant
that grows in a huge swath of climates,” adds
Gambetta. “But climate change will pose serious
challenges, especially to these traditional wine-
growing regions.”
Page 7
What is an Oregon AVA?
By Rusty Savage
23 Wine Regions in Oregon and What it Means
Oregon is home to 23 federally
recognized grape growing areas, known
as American Viticulture Areas or AVAs.
These wine regions are the backbone of the
Oregon wine industry.
Columbia Gorge AVA, There are no nested
AVAs inside the Columbia Gorge AVA.
Columbia Valley AVA. There are two
nested Oregon AVAs inside the larger
Columbia Valley AVA.
The Rocks District of Milton-Freewater
AVA
Walla Walla Valley AVA
Rogue Valley AVA, There is one nested
AVA inside the larger Rogue Valley AVA.
Applegate Valley AVA
Snake River Valley AVA, There are no
nested AVAs inside the Snake River Valley
AVA.
Southern Oregon AVA, The Southern
Oregon AVA is home to the Rogue Valley,
Umpqua Valley, and their respected nested
AVAs.
Rogue Valley AVA
Umpqua ValleyAVA,There are two nested
AVAs inside the larger Umpqua Valley
AVA.
Elkton AVA
Red Hill AVA
Willamette Valley AVA, There are eleven
nested AVAs inside the larger Willamette
Valley AVA. (Not listed here)
In North Douglas county, the Umpqua
Valley is home to the Umpqua Valley AVA,
nested within the Southern Oregon AVA.
This is mainly the region encompassing the
greater Roseburg area and on the north and
northwest portion of this wine region, are
the Red Hill AVA to the north and west and
the Elkton AVA in the north and western
region. Some of the outstanding qualities
of these 3 AVA regions are listed below and
may well fortell the future significance and
influence on future wine production.
Umpqua Valley AVA, Douglas County,
Established 1984
Umpqua Valley continues to evolve as new
winemakers discover the area, bringing
with them a passion for innovation and
world-class wine.
Location
Umpqua Valley sits between the Coast
Range to the west and the Cascades to the
east, with the Willamette Valley to the north
and the Rogue Valley, south. Named for the
legendary fishing river that runs nearby, the
appellation stretches 65 miles from north to
south, and is 25 miles from east to west.
Climate
The Umpqua Valley can successfully
grow both cool and warm varieties. It’s
comprised of three distinct climatic sub-
zones: 1) The northern area around the
town of Elkton enjoys a cool, marine-
influenced climate. It receives around 50
inches of annual rainfall, making irrigation
unnecessary. Pinot Noir and other cool-
climate varieties thrive here. 2) The central
area to the northwest of Roseburg has an
intermediate climate where both cool and
warm varieties do well. 3) The area south of
Roseburg is warmer and more arid, similar
to Rogue and Applegate valleys to the
south, making irrigation a necessity. Warm-
climate varieties, including Tempranillo,
Syrah and Merlot flourish here.
Soils
Umpqua Valley soils are as varied as the
climate. Generally, they are derived from
a mix of metamorphic, sedimentary and
volcanic rock; though more than 150 soil
types have been identified in the region.
The valley floor levels have mostly deep
alluvial or heavy clay materials, while
the hillsides and bench locations have
mixed alluvial, silt or clay structures — all
excellent for winegrowing.
Topography
The complex topography of the Umpqua
Valley is a result of the collision of three
mountain ranges of varying age and
structure: Klamath Mountains, Coast
Range and Cascades. Many say the area
should not be thought of as a single valley,
but, rather, more accurately the “Hundred
Valleys of the Umpqua” because it is made
up of a series of interconnecting small
mountain ranges.
Varieties Grown
Albariño, Baco Noir, Cabernet Franc,
Cabernet
Sauvignon,
Chardonnay,
Dolcetto, Gewürztraminer, Graciano,
Grenache, Malbec, Merlot, Muscat
Canelli, Pinot Blanc, Pinot Gris, Pinot
Noir, Riesling, Sauvignon Blanc, Semillon,
Syrah, Tempranillo, Zinfandel.
Elkton AVA, North Douglas County,
Established 2015
Winegrowing in Elkton dates to the early
’70s when Ken Thomason began planting
cool climate whites and Pinot Noir. The
first winery was established in 2000.
Currently, there are six licensed wineries
and 8 commercial vineyards, totaling 96.5
planted acres.
Location
Located in North Douglas County, the AVA
is 33 miles from the Pacific Ocean, with
the Cascade Range to the east, Willamette
Valley to the north and Rogue Valley to the
south. A part of the Umpqua Valley AVA, it
is named for the town of Elkton and claims
the northernmost and lowest elevation
region in the Umpqua.
Climate
Elkton Oregon is the coolest and wettest
region within the larger Umpqua Valley
and produces different varieties and
different wine styles than the rest of the
larger AVA. Elkton enjoys a cool, marine-
influenced climate with a longer growing
season than the rest of the Umpqua. The
region receives about 50 inches of rain
each year.
Soils
The AVA is dominated by the coastal
mountain geology, lying over a
combination of sedimentary, volcanic
and metamorphic rock from the middle
Eocene. More than 50 different soil
series or complexes are present, made up
of mostly residual clay and/or silt loam
soil or cobble-rich alluvial deposits from
the Yamhill and Tyee formation, and the
Umpqua River terrace.
Topography
Elkton Oregon contains a wide range of
terrain dissected by the broader meanders
of the Umpqua River. The majority of the
AVA falls below the 1,000-foot contour and
includes the river bottom land — elevation
130 to 160 feet — as well as river terraces
and foothills near the river — also 130 to
160 feet.
Varieties Grown
Baco Noir, Chardonnay, Gewürz., Pinot
Gris, Pinot Noir, Riesling, Syrah.
Red Hill AVA, Douglas County,
Established 2005
The Applegate and Scott families, pioneers
of Southern Oregon, settled at the foot of
Red Hill in the mid-1800s. Jesse Applegate
planted Douglas County’s first established
vineyard in Yoncalla in 1876.
Location
Red Hill Douglas County is a sub-
appellation of the Umpqua Valley near the
small town of Yoncalla, which lies about
30 miles north of Roseburg and parallels
Interstate 5. It encompasses 5,500 acres
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