Impact of climate change on Medicinal and aromatic plants: Review

Abstract

There has been worldwide changes in seasonal patterns, weather events, temperature ranges, and other related phenomena and all have been analyzed in partial, reported and attributed to global climate change. The negative impacts of climate change will become much more intense and frequent in the future—particularly if environmentally destructive human activities continue unabated, warned categorically by a number of experts in a wide range of scientific disciplines and interests. Medicinal and aromatic plants (MAPs) are not immune to the effects of climate change like all other living members of the biosphere. Clear signals are coming on climate change impact which is causing noticeable effects on the lifecycles and distributions of the world's vegetation, including wild MAPs across the world. This in turn causing some MAPs endemic to geographic regions or ecosystems which could put them at risk and are particularly vulnerable to climate change. Such serious issues and challenges are a continuous concern with regard to the survival and genetic integrity of some MAPs and are being discussed within various forum and platform. Further, such issues of climate change will definitely pose a more prominent or immediate threat to MAP species than other threats, however, scientists do not know whether climate change has the potential to exert increasing pressures upon MAP species and populations. Climate change impact may have a tremendous possible effect on MAPs particularly significant due to their value within traditional systems of medicine and as economically useful plants. At this stage, the future effects of climate change are largely uncertain more so with MAPs, but current evidence suggests that these phenomena are having an impact on MAPs and that there are some potential threats worthy of concern and discussion.

Full text

1Principal Scientist (Plant Physiology) (e mail:
manishdas50@gmail.com), 2Principal Scientist (Plant Physiology),
Education Division. 3Agriculture and Horticulture Commissioner,
Ministry of Agriculture, Government of India, New Delhi.
Research Review Articles
Indian Journal of Agricultural Sciences 86 (11): 1375–82, November 2016/Review Article
Impact of climate change on medicinal and aromatic plants: Review
MANISH DAS1, VANITA JAIN2 and S K MALHOTRA3
Horticultural Science Division, Indian Council of Agricultural Research, KAB-II, New Delhi 110 012
Received: 13 August 2015; Accepted: 8 July 2016
ABSTRACT
There has been worldwide changes in seasonal patterns, weather events, temperature ranges, and other related
phenomena and all have been analyzed in partial, reported and attributed to global climate change. The negative
impacts of climate change will become much more intense and frequent in the future—particularly if environmentally
destructive human activities continue unabated, warned categorically by a number of experts in a wide range of
scientific disciplines and interests. Medicinal and aromatic plants (MAPs) are not immune to the effects of climate
change like all other living members of the biosphere. Clear signals are coming on climate change impact which is
causing noticeable effects on the lifecycles and distributions of the world’s vegetation, including wild MAPs across the
world. This in turn causing some MAPs endemic to geographic regions or ecosystems which could put them at risk and
are particularly vulnerable to climate change. Such serious issues and challenges are a continuous concern with regard
to the survival and genetic integrity of some MAPs and are being discussed within various forum and platform.
Further, such issues of climate change will definitely pose a more prominent or immediate threat to MAP species than
other threats, however, scientists do not know whether climate change has the potential to exert increasing pressures
upon MAP species and populations. Climate change impact may have a tremendous possible effect on MAPs
particularly significant due to their value within traditional systems of medicine and as economically useful plants. At
this stage, the future effects of climate change are largely uncertain more so with MAPs, but current evidence suggests
that these phenomena are having an impact on MAPs and that there are some potential threats worthy of concern and
discussion.
Key words: Adaptation, Climate change, Elevated CO2, Medicinal and aromatic plants, Phenology, Plant
constituents, Weather events
Earth’s climate is warming at an unprecedented rate
which is evidenced unequivocally. Sea levels are rising and
impacting plant’s growth and yield due to climatic effects.
There are prolonged droughts in arid and semi-arid regions,
increased flooding in mid to high latitudes, increase in
extreme weather events etc. (Tack et al. 2015). There is a
high risk of mass extinction of biodiversity as the planet
warms and climate is changing more rapidly than species
can adapt (Lindzen 1990, Das 2010a). There is need to
understand the pattern of climate change which is one of
the most important global environmental challenges and
more specifically different types of impacts are to be
understood and assessed, vulnerabilities need to be
addressed, while adaptation strategies have to be
developed through prioritizing the cause and the impacts
(Cavaliere 2009, Courtney 2009). In the flip side of it,
production enterprises and practices in agriculture are
adapted to variability in local climate conditions, as farmers
3
have specifically developed strategies for responding to
weather patterns that have prevailed over a period of time
in their given region (Marshall et al. 2015) and more so
with medicinal plants like Isabgol, Asalio and many other
important ones (Das 2010a, b) in arid and semi-arid
condition.
To encourage nations to conserve their plant and
animal species the United Nations declared 2010 as the
Year of Biodiversity coupled with signing The Convention
on Biological Diversity (CBD) more than a decade ago. But
there is a continuous disappearance of species worldwide
at a rapid rate claimed by local communities in various
regions who have used medicinal plants for generations.
Further, they said that these species are becoming difficult
to find, which according to them could be due to climate
change as a factor.
As a direct result of CBD, the Biological Diversity Act
was enacted in 2002. A National Biodiversity Strategy and
Action Plan (NBSAP) was prepared and subsequently a
National Biodiversity Authority (NBA) was constituted.
However, significant initiative under this Act by NBA for
the conservation and sustainable use of medicinal plants
is awaited or, more importantly, and the preservation of

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4
traditional knowledge, innovations and practices of
indigenous and local communities or their wider application
is needed. Any restrictions with regard to regulatory
functions need to be understood and made viable on case
to case basis with much emphasis to know the impact of
climate change on MAPs.
Is there a big loss of medicinal plant species in India?
To systematically assess and enlist the decline and
loss of medicinal plant species and to monitor and assess
threat to wild populations of prioritized species (Denyer
2007), an institutional mechanism needs to be put in place.
Article 8d of CBD specifically states: ‘Promote the protection
of ecosystems, natural habitats and the maintenance of
viable populations of species in natural surroundings.’
However, the Ministry of Environment and Forest (MoEF),
has to have long-term programme, strategy or dedicated
funding for monitoring viable populations and undertaking
assessment of medicinal plants. National Medicinal Plants
Board and Indian Council of Agricultural Research located
at New Delhi may have to take the lead in this direction.
To further substantiate, on a relatively small scale, some
efforts have been undertaken using IUCN Red List
Categories and Criteria (Bhardwaj et al. 2007). According
to such studies, 335 wild medicinal plants of India have
been identified as being under various categories of threat
of extinction ranging from Near Threatened, Vulnerable,
Endangered to Critically Endangered. Eighty-four of these
species of conservation concern were recorded in high
volume trade (Bhardwaj et al. 2007). However, it’s a
continuous cycle and such kind of species are believed to
be threatened, if sincere efforts are not taken.
Significant loss of diversity and its impact
Arguably, there are six plant species of high
conservation concern. These are Aconitum heterophyllum,
Coscinium fenestratum, Decalepis hamiltonii, Picrorhiza
kurroa, Saraca asoca and Taxus wallichiana (Malcolm et
al. 2006, Bhardwaj et al. 2007). These species are valuable
medicinal plants which are currently being used in high
quantities by India’s herbal industry leading to rapid decline
of their populations in wild and is of utmost concern. To
reiterate the fact, the plant materials of these species are
obtained entirely from the wild and their medicinal uses are
described in the codified Indian systems of medicine,
namely Ayurveda, Siddha and Unani.
These species are being used to treat many disease
conditions, namely inflammatory, analgesic, anti-diarrhoeal,
antipyretic, anti-diabetic, anti-cancer, in liver diseases as
well as gynaecological disorders. The decline of these
species will adversely affect the current usage for health
care and treatment of such conditions. Further, their
extinction will be an irreparable loss to the wild gene pool,
which evolved over several millennia. It is to be understood
that once lost, these species will not be reproducible
through any synthetic means. It will be a huge loss for our
future generations to suffer.
Losses because of climate change or because of over
exploitation?
The decline and loss of wild populations of valuable
wild Indian medicinal plants is due to the combined impact
of habitat loss, its degradation, as well as over-exploitation
(Goswami et al. 2006). Climate change is also cited as a
reason but no serious studies have been undertaken in
our country for medicinal plants in particular (Harish et al.
2012). However, a few recent studies, outside India, have
speculated about the fragmentation and decline of wild
populations of some plant species in the mountains
ecosystems due to climate change (Thomas et al. 2004).
Medicinal plants constitute around 40% of the known
diversity of vascular plant species of India. Conservation
of Indian flora merits high priority (Goswami et al. 2006). A
national agenda for conservation of medicinal plants should
be made.
Climate change challenges for medicinal plants
Although the terms “global warming” and “climate
change” are often used interchangeably, “climate change”
is often the preferred term of many environmental
organizations and government agencies (IPCC 2007). Climate
change refers to any significant change in measures of
climate (such as temperature, precipitation, or wind) over
an extended period of time (decades or longer). Global
warming refers to an increase in the temperature of the
atmosphere that can contribute to change in global climate
patterns. The Intergovernmental Panel on Climate Change
considers “climate change” to mean any change in climate
over time, whether due to natural variability or as a result
of human activity (IPCC 2007). The United Nations
Framework Convention on Climate Change defines “climate
change” as a change in climate that is attributable directly
or indirectly to human activity that alters atmospheric
composition.
The success of mankind’s ability to meet the challenges
of climate change will depend on how well it conserves the
existing biodiversity of plants species including valuable
medicinal and aromatic plants. Governments will have to
act now, if plants are to continue to provide the resources
and ecosystem services upon which all other species
depend.
Wild plant conservation has three mutually dependent
aims: (i) Maintaining plant species and their genetic
diversity. (ii) Achieving sustainable use of wild plant
resources. (iii) Securing plants and natural vegetation as
providers of ecosystem services.
These aims are most likely to be achieved where efforts
are focused on maintaining plants within robust
ecosystems. However, the ability of national government
to achieve these aims is under increasing pressure because
of climate change; the impact of which is already visible at
all levels of species’ survival and conservation. A
continuing and stoppable shift in the potential ranges of
many plant species, causing them to become extinct in their
existing locations is a reality. Many will find it difficult to

1377November 2016] IMPACT OF CLIMATE CHANGE
5
‘follow the climate’, lacking adequate means of dispersal
and finding their paths being impeded by human
destruction of wild habitats (Hawkins et al. 2008).
Like all living members of the biosphere, medicinal and
aromatic plants (MAPs) are not immune to the effects of
climate change. Climate change is causing noticeable effects
on the lifecycles and distributions of the world’s vegetation,
including wild MAPs. Some MAPs are endemic to
geographic regions or ecosystems particularly vulnerable
to climate change, which could put them at risk (Neilson et
al. 2005). Concerns regarding the survival and genetic
integrity of some MAPs in the face of such challenges are
increasingly being discussed within various fora at all levels
to understand the gravity of the situation.
To believe it more scientifically, wild plants play a
fundamental role in enabling national governments to
sustain delivery of social and economic development and
climate change magnifies the significance of this role. The
critical factor to understand in securing sustainable
management of national plant resources is how
governments involve the people and groups for whom the
resources have most value.
Climate change is affecting medicinal and aromatic
plants around the world and could ultimately lead to losses
of some key species. This conclusion is based on the
research, observations, and opinions of multiple medicinal
plant researchers and conservationists, as reported in the
cover article of the latest issue of HerbalGram (Cavaliere
2008, 2009), the quarterly journal of the American Botanical
Council (ABC).
The study has noted the endemic nature of the species
to different regions or ecosystems that are especially
vulnerable to climate change, such as Arctic and alpine
regions, and could be at maximum risk (Cavaliere 2008).
For example, Rhodiola rosea of the Canadian Arctic and
snow lotus (Saussurea laniceps) of the Tibetan mountains
are medicinal species that face significant threats from
climate change.
The study further explores effects of climate change
that appear to be impacting plants including medicinal plants
throughout the world. For example, climate change has led
to shifts in seasonal timing and/or ranges for many plants,
which could ultimately endanger some wild medicinal plant
populations. To add to the list, extreme weather events,
meanwhile, have begun to impact the production and
harvesting of various medicinal plants around the world.
For instance, recent abnormally hot summers have
prevented reseeding of medicinal plants such as chamomile
(Matricaria recutita) in Germany and Poland, and
increasingly severe flooding in Hungary has reduced
harvests of fennel (Foeniculum vulgare) and anise
(Pimpinella anisum) in that country (Pompe et al. 2008).
Although, the primary focus of this article concerns
medicinal plants, much of the threat to these plants includes
aromatic plants harvested for their essential oils, which
could be used for medicinal, fragrance, culinary, and/or
other purposes (Cavaliere 2009, Tack et al. 2015).
Climate change impact on medicinal and aromatic plants
Climate change has become one of the greatest
challenges to humankind and all other life on Earth.
Worldwide changes in seasonal patterns, weather events,
temperature ranges, and other related phenomena were
reported and attributed to global climate change. Numerous
experts in a wide range of scientific disciplines have warned
that the negative impacts of climate change will become
much more intense and frequent in the future—particularly
if environmentally destructive human activities continue
unabated (Walther et al. 2002). There is concern over its
overall impact affecting secondary metabolites of many
medicinal plants which are very important economically and
commercially.
Although scientists do not know whether climate
change poses a more prominent or immediate threat to
MAP species than other threats, it does have the potential
to exert increasing pressures upon MAP species and
populations in the coming years. The possible effects on
MAPs may be particularly significant due to their value
within traditional systems of medicine and as economically
useful plants. The future effects of climate change are
largely uncertain, but current evidence suggests that these
phenomena are having an impact on MAPs and that there
are some potential threats worthy of concern and
discussion.
Some studies have demonstrated that temperature
stress can affect the secondary metabolites and other
compounds that plants produce, which are usually the basis
for their medicinal activity (Schar et al. 2004). But few
studies were conducted in-situ or ex-situ to mimic
conditions of global warming (Das et al. 1999).
The taste and medicinal effectiveness of some Arctic
plants could possibly be affected by climate change (Gore
2006). It was noted that such changes could either be
positive or negative, although it seems more likely that the
effects would be negative since, secondary metabolites are
produced in larger quantities under stressed conditions
and for Arctic plants, warmer temperatures would likely
alleviate environmental stress. However, the production of
plants’ secondary metabolites are influenced by diseases,
competition between plants, animal grazing, light exposure,
soil moisture, etc. and these factors may mitigate the effects
of climate change on plants’ secondary metabolites (Dean
2007).
Through collection of samples of medicinal plant
species from Greenland, NordGen, an organization based
in Alnarp, Sweden could go for preservation and evaluation
of Angelica (Angelica archangelica, Apiaceae), yarrow
(Achillea millefolium, Asteraceae), Rhodiola rosea (aka
golden root, Crassulaceae), and thyme (Thymus vulgaris,
Lamiaceae). These four MAPs are not currently endangered
in Greenland, nor are they currently listed on the
Convention in Trade in Endangered Species (CITES)
appendices (Pal et al. 2004). However, collectors interested
in preserving current plant genotypes from rapidly warming
areas, such as Greenland, must do so before new genotypes

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DAS ET AL.
6
arrive in response to climate change. Moreover, plant
populations in Greenland are often isolated by the territory’s
many huge ice sheets, and this can limit the populations’
available gene pools and subsequent abilities for
genetically adapting to new climatic conditions. Capturing
genetic diversity becomes increasingly important since it
is possible that populations will lose genetic diversity in
response to the changing environment.
Some cold-adapted plant species in alpine
environments have begun to gradually climb higher up
mountain summits—a phenomenon correlated with warming
(Held et al. 2005). In some cases, these plants migrate
upward until there are no higher areas to inhabit, at which
point they may be faced with extinction. Additionally, the
upward migration of plant species can lead to increased
competition for space and resources, causing further stress
among alpine plant populations.
A Global team found that useful Tibetan plants
(predominantly medicinal plants) accounted for 62% of all
plant species in the alpine Himalayan sites that they
examined (Bhardwaj et al. 2007). Further, although overall
species richness was found to decline with elevation from
the lowest summits to the highest, the proportion of useful
plants stayed approximately constant. This high percentage
of useful plants confirms the importance of the Himalayas
for Tibetan medicine and reflects the dangers posed by
potential plant losses from climate change.
However, a few medicinal alpine species are restricted
to the upper alpine zone, such as Artemisia genipi
(Asteraceae) and Primula glutinosa (Primulaceae). These
species may experience greater impacts from warming
temperatures, possibly leading to local endangerment (Pal
et al. 2004).
Medicinal and aromatic plants in other threatened
regions
Although Arctic and alpine areas are experiencing
some of the most rapid changes from global warming, other
ecosystems are also considered particularly threatened by
the ongoing effects of climate change, e.g. islands and
rainforests (Dean 2007). Islands are considered especially
at risk from rising ocean levels, in addition to changing
temperatures and weather patterns. The world’s oceans also
absorb excess heat from the atmosphere, and as water
warms it expands in volume which will similarly contribute
to global sea level rise (Walther et al. 2002).
Despite these threats, experts have indicated that island
MAPs may not be significantly affected by conditions
related to climate change. Many of the plants used by
island communities are common species that are widespread
and highly adaptable.
Common medicinal plants of the Pacific islands include
noni (Morinda citrifolia, Rubiaceae), naupaka (Scaevola
spp., Goodeniaceae) kukui (Aleurites moluccana,
Euphorbiaceae), and milo (Thespesia populnea, Malvaceae).
These and other medicinal plant species of the area grow
relatively fast, have high reproduction rates, and are
typically resistant to salt water and wind, making them more
resilient to some of the predicted effects of global climate
change (Law and Salick 2005, Walther et al. 2002).
Similarly, medicinal plants of the Mediterranean islands
do not appear to be under any considerable threat from
conditions of climate change (Yoon 1994). According to de
Montmollin, most wild collected MAPs, such as thyme
(Thymus spp., Lamiaceae) and rosemary (Rosmarinus spp.,
Lamiaceae), are rather widespread and located at lower
altitudes, making them less vulnerable to climate change
than plants with narrower ecological requirements
(Parmesan and Yohe 2003). Rainforest ecosystems are also
considered to be threatened by climate change. Climate
modeling studies have indicated that these regions are
likely to become warmer and drier, with a substantial
decrease in precipitation over much of the Amazon (Neilson
et al. 2005).
There is not much, if any, published evidence on
MAPs that could be at risk in the rainforest from climate
change, and experts are unable to comment on specific
MAPs that may be vulnerable to climate change in
rainforests. However, the expected loss of general
biodiversity in the Amazon, as noted in the IPCC report,
indicates the potential to lose both known and
undiscovered MAP species (IPCC 2007).
Widespread effects of climate change
It appears that there is worldwide effects of climate
change on plants. For instance, evidence has shown that
climate change has been affecting vegetation patterns such
as phenology (the timing of lifecycle events in plants and
animals, especially in relation to climate) and distribution
(Cleland et al. 2007). Some wild plants, including MAPs,
have begun to flower earlier and shift their ranges in
response to changing temperatures and weather. Shifting
phenologies and ranges may seem of little importance at
first glance, but they have the potential to cause great
challenges to species’ survival. Further, they serve as
harbingers of future environmental conditions from climate
change. Increased weather extremes are also predicted to
accompany climate change, and plant species’ resilience in
the face of these weather events may also factor into their
abilities to adapt and survive.
Few studies conducted on effect of atmospheric CO2
enrichment on specific plant compounds of direct medicinal
value. Such studies revealed that under controlled well-
watered conditions in a phytotron, tripling of the air’s CO2
content increased dry weight production of medicinal plants
of woolly foxglove (Digitals lanata EHRH), which
produces the cardiac glycoside digoxin that is used in the
treatment of cardiac insufficiency by 63% while under
water-stressed conditions the CO2 induced dry weight
increase was 83% (Stuhlfouth et al. 1987). Results further
revealed that a near-tripling of the air’s CO2 concentration
led to 75% increase in plant dry weight production/unit
land area and 15% increase in digoxin yield/unit dry
weight of plant, which combined to produce an actual

1379November 2016]
7
IMPACT OF CLIMATE CHANGE
doubling of total digoxin yield/ha of cultivated land
(Stuhlfauth and Fock 1990).
Shifts in phenology
The lifecycles of plants correspond to seasonal cues,
so shifts in the timing of such cycles provide some of the
most compelling evidence that global climate change is
affecting species and ecosystems (Cleland et al. 2007).
Available evidence indicates that spring emergence has
generally been occurring progressively earlier since the
1960s. Such accelerated spring onset has generated
noticeable changes in the phenolgical events of many plant
species, such as the timing of plants’ bud bursts, first
leafings, first flowerings, first seed or fruit dispersal, etc.
Studies and records indicate that many plants including
MAPs have started blooming earlier in response to the
earlier occurrences of spring temperatures and weather. It
needs further in-depth experimentation and revealing of
facts in MAPs.
There is a lot of variability between species, and it is
difficult to predict how climate change affects the
phenologies of different plants. In one finding it was
reported that phenological shifts of medicinal plants were
not significantly affecting wild harvesting practices (Cleland
et al. 2007). It was noted that there was always variations
in the timing of the seasons, and collectors of wild medicinal
plants are accustomed to adjusting their harvesting
schedules accordingly.
Early blooming can be detrimental if an area is prone
to cold spells late in the spring season. If a cold spell
occured a few days or weeks after early blooming has
commenced, then those early buds or fruits froze,
potentially killing or affecting the production of some
economically useful plants (Zobayed et al. 2005). Apple
orchards of North Carolina suffered severely from this type
of scenario four years back, and the medicinal plant
bloodroot (Sanguinaria canadensis, Papaveraceae) is also
susceptible to frost following early blooming (Shea 2008).
The impact of extreme weather events
Studies, surveys and mounting evidence indicates that
extreme weather events such as storms, droughts, and
floods have become more prevalent and intense across the
globe in recent years (Neilson et al. 2005). The frequency
and severity of these events are expected to increase in
the future as a result of continued warming, having negative
effects on human health, infrastructure, and ecosystems.
Extreme weather events have been known to affect
harvesters’ and cultivators’ abilities to grow and/or collect
medicinal plant species, as reported in recent years.
Extreme weather conditions throughout Europe are
impacting medicinal plant production from seeding to
harvesting, such as chamomile in Germany and Poland
(Pompe et al. 2008). In the first year fennel (Foeniculum
vulgare, Apiaceae) was recorded as having no yield at all
in Bulgaria, due to drought conditions during the spring in
that country. Due to long and dry summers in Serbia,
accompanied by other extreme weather conditions such as
strong rains and winds, have sometimes made it impossible
for harvesters to perform second cuttings of the aerial parts
of cultivated herbs such as peppermint (Pal et al. 2004,
Schar et al. 2004).
Medicinal plants in other continents have also been
impacted by severe weather conditions. Africa’s Sahel
region experienced one of the most severe droughts of the
20th century. In Africa, medicinal plants of the Sahel include
hibiscus (Hibiscus sabdariffa, Malvaceae), myrrh
(Commiphora africana, Burseraceae), frankincense
(Boswellia spp., Burseraceae), baobab (Adansonia
digitata, Malvaceae), moringa (Moringa oleifera,
Moringaceae), and various aloes (Aloe spp., Liliaceae).
These were affected due to severe drought (Held et al.
2005). Future droughts due to climate change could
have devastating effects on the region’s already
suffering ecosystems and harvesting capabilities (Idso et
al. 2000).
In India, where climate is largely controlled by an
annual monsoon, appears to be experiencing increasingly
severe and erratic precipitation. A recent study found that
the overall amount of monsoon rainfall across central India
has remained relatively stable over the past century;
however, moderate rainfall events during monsoon have
significantly decreased while extreme rainfall events have
greatly increased since the early 1980s (Bhardwaj et al.
2007). This increase in extreme rainfall events indicates
greater potential for future natural disasters. Experts have
claimed that the frequency and intensity of flooding has
likewise been increasing in India in recent years, and
hailstorms have caused huge agricultural losses across
areas of India lately. Therefore, such events are to be
understood and their impact on MAPs need to be
diagnosed.
States like Gujarat and Rajasthan experienced
hailstorms and rains in 2006, 2007 and 2008, at times when
such events traditionally have not occurred within the past
50 years. Hail and rainstorms have also damaged psyllium
(Plantago ovata, Plantaginaceae), wheat (Triticum
aestivum, Poaceae), and cumin (Cuminum cyminum,
Apiaceae) crops in the area. The destruction of Indian
psyllium crops from hail and rainstorms resulted in a smaller
than usual annual yield for 2008. Similarly, it was noted
that the availability of menthol crystals was affected by
heavy monsoon rainfall, which occurred earlier than usual
in Northern India and reportedly damaged wild mint (Mentha
arvensis, Lamiaceae) crops in 2008 (Bhardwaj et al. 2007).
Such hailstorms and rains are common factors to impact
MAPs in general.
Hurricane seasons could also be affected by climate
change, although experts do not agree on the possible
effects (Dean 2007). Some experts believe that hurricanes
will increase in frequency, duration, and intensity; others
predict that hurricanes will either not be significantly
affected or might even be inhibited by factors related to
warming. Regardless, shifts (whether increasing or

1380 [Indian Journal of Agricultural Sciences 86 (11)
8
DAS ET AL.
decreasing) in hurricane activity have the potential to affect
the availability of medicinal plants.
Linkages between climate change, plants and livelihoods
Vast population of world’s poor depend directly on
harvesting non-timber forest products, edible, medicinal and
aromatic plants for livelihood and sustenance. Many of
these species are under threat from increasing human
pressure and loss of natural vegetation accentuated further
by climate change. Consequently, the people who depend
on them are affected.
Several chemicals derived from medicinal and aromatic
plants are historically acknowledged as having
pharmaceutical value (Table 1) (Ziska 2005). Even in
developed countries, where synthetic drugs dominate, 25%
of all prescriptions dispensed from community pharmacies
from 1959 through 1980 contained plant extracts or active
principles prepared from higher plants. For developing
countries, however, the World Health Organization (WHO)
reported that more than 3.5 billion people rely on plants as
components of their primary health care. In both developed
and developing countries, there are a number of
economically important pharmaceuticals derived solely from
plants (e.g. tobacco), with high economic value.
An analysis of threat and potential for medicinal plants
The effects of climate change are apparent within
ecosystems around the world, including medicinal and
aromatic plant populations. Medicinal and Aromatic Plants
(MAPs) in Arctic and alpine areas face challenges
associated with their rapidly changing environments, and
some researchers have raised concerns regarding the
possible losses of local plant populations and genetic
diversity in those areas. Shifting phenologies and
distributions of plants were recorded worldwide, and these
factors could ultimately endanger wild MAP species by
disrupting synchronized phenologies of interdependent
species, exposing some early-blooming MAP species to
the dangers of late cold spells, allowing invasives to enter
MAP species’ habitats and compete for resources, and
initiating migratory challenges, among other threats. Extreme
weather events already impact the availability and supply
of MAPs on the global market, and projected future
increases in extreme weather are likely to negatively affect
MAP yields even further.
Climate change may not currently represent the biggest
threat to MAPs, but can be a greater threat in future
decades (Idso et al. 2000). Poor people rely on medicinal
plants not only as their primary healthcare option, but also
as a significant source of income. The potential loss of
MAP species from effects of climate change is likely to
have major ramifications on the livelihoods of large numbers
of vulnerable populations across the world. Further, the
problems associated with climate change are likely to be
much more difficult to combat than other threats to MAPs.
The problems posed by warming temperatures, disrupted
seasonal events, extreme weather, and other effects of
climate change, on the other hand, cannot be so quickly
and easily resolved.
Implication and studies
Climate change is already happening and its effects
will certainly increase in the years ahead due to increasing
temperature and variability of rainfall. The effects of climate
change on medicinal plants, in particular, has not been well-
studied and is not fully understood. But, it is evident that
with changing climatic conditions plants may up shift,
change their structure and habitat etc. Climate change is
already causing noticeable effects on lifecycle/distribution
of the world’s vegetation. As the situation unfolds, climate
change may become a more pressing issue for the herbal
community, potentially affecting users, harvesters and
manufacturers of MAP species.
There is an urgent need to assess the effect of climate
change and global warming and particularly effect of
elevated CO2 on medicinal and aromatic plants with a
focused approach especially on the accumulation of
secondary metabolites (Courtney 2009, Harish et al. 2012).
The research on medicinal plants is sporadic and
insignificant and it is high time that these group of plants
as potential sources of neutraceuticals are given due
attention. A number of studies are required to be carried
Table 1 Plant-derived pharmaceutical drugs and their clinical
usage. Although many of these drugs are synthesized
in developing countries, the World Health Organization
estimates that as many as 3.5 billion people still rely
on botanical sources for medicines (WHO, 2002). Recent
work on atropine and scopolamine indicates that
increasing carbon dioxide and/or temperature will alter
the concentration and or production of these plant-
derived compounds (Ziska 2005)
Drugs Action/Clinical use Species
Acetyldigoxin Cardiotonic Digitalis lanata
Allyl Rubefacient Brassica nigra
isothiocyanate
Atropine Anticholinergic Atropa belladonna
Berberine Bacillary dysentery Berberis vulgaris
Codeine Analgesic, antitussive Papaver somniferum
Danthron Laxative Cassia spp.
L-Dopa Anti-Parkinson’s Mucuna spp.
Digitoxin Cardiotonic Digitalis purpurea
Ephedrine Antihistamine Ephedra sinica
Galanthamine Cholinesterase Lycoris squamigera
inhibitor
Kawain Tranquilizer Piper methysticum
Lapachol Anticancer, antitumor Tabebuia spp.
Ouabain Cardiotonic Strophantus gratus
Quinine Antimalarial Cinchona ledgeriana
Salicin Analgesic Salix alba
Taxol Antitumor Taxus baccata/
T. wallichiana
Vasicine Cerebral stimulant Vinca minor
Vincristine Antileukemic agent Catharanthus roseus

1381November 2016]
9
IMPACT OF CLIMATE CHANGE
out which are as follows: 1. Systematic list of overall RET
species of MAPs. 2. Impact on phenology of plants as
well as morpho-physiological and biochemical parameters
in controlled environments and field. 3. Varietal improvement
on biotic and abiotic stress and to assess the genetic
integrity of MAP species. 4. Standardization of techniques
for long term exposure of high CO2 and temperature on
MAPs and development of innovative techniques to study
the impact of CO2 enrichment and high temperature as in
Eucalyptus camaldulensis (Kirdmanee et al. 1995) and
Rehmannia glutinosa (Seon et al. 1995). 5. Develop
strategies for conservation of endangered flora and fauna
of medicinal and aromatic value. 6. Organic farming
practices of MAPs for conservation of medicinal properties.
7. Compilation of indigenous knowledge of herbal, medicinal
and aromatic plants cultivation against elements of climate
change. 8. Changes in the composition of secondary
metabolites in diverse climatic situations.
The possible effects on MAPs may be particularly
significant due to their immense value in traditional system
of medicine and for economic usefulness. Although future
effects of climate change are uncertain, but this will have
an impact on MAPs, and has potential to become much
greater threat in future. Potential loss of some MAPs may
affect livelihood of large number of people. The problem of
warming temperature and disrupted seasonal events also
cannot be easily understood, but timely interventions can
certainly prevent the loss of biodiversity. The impact of
climate change on medicinal plants both cultivated and
wild is very significant. The need of the hour is to have a
focused research approach especially on the accumulation
of secondary metabolites of health significance (Harish et
al. 2012). The research on medicinal plants with respect to
climate change is very sporadic and insignificant in
comparison with other commercial crops. It is the high time
that, these group of plants should not be left as they are
potential sources of bio-molecules and neutraceuticles.
REFERENCES
Bhardwaj J, Singh S and Singh D. 2007. Hailstorm induced crop
losses in India: some case studies. Abstract for presentation
at 4th European Conference on Severe Storms in Trieste, Italy,
10–14, September 2007.
Courtney C. 2009. The effects of climate change on medicinal
and aromatic plants. HerbalGram (American Botanical
Council) 81: 44–57.
Cavaliere C. 2008. Drought reduces 2007 saw palmetto harvest.
HerbalGram 77: 56–7.
Cavaliere C. 2009. The effects of climate change on medicinal
and aromatic plants. HerbalGram 81: 44–57.
Cleland E E, Chuine I, Menzel A, Mooney H A and Schwartz M
D. 2007. Shifting plant phenology in response to global change.
Trends in Ecology and Evolution 72(7): 357–64.
Das Manish. 2010a. Performance of Asalio (Lepidium sativum L.)
genotypes under semi-arid condition of middle Gujarat. Indian
Journal of Plant Physiology 15(1): 85–9.
Das Manish. 2010b. Growth, photosynthetic efficiency, yield
and swelling factor in Plantago indica under semi-arid
condition of Gujarat, India. Indian Journal of Plant
Physiology 15(2): 125–32.
Das Manish, Zaidi P H, Pal M and Sengupta U K. 1999. Carbon
dioxide enrichment effect on growth and development of some
crops. Journal of Agronomy and Crop Science 181: 221–5.
Dean C. 2007. Will warming lead to a rise in hurricanes? New
York Times. May 29, 2007; F5.
Denyer S. 2007. Floods find India wanting as climate change
looms. Hindustan Times. 8 August, 2007.
Gore A. 2006. An Inconvenient Truth. Rodale, New York.
Goswami B N, Venugopal V, Sengupta D, Madhusoodanan M S
and Xavier P K. 2006. Increasing trend of extreme rain events
over India in a warming environment. Science 314: 1 442–5.
Harish B S, Dandin S B, Umesha K and Sasanur A, 2012. Impact
of climate change on medicinal plants - A review, Anc Sci Life.
32 (Suppl 1): S23.
Held I M, Delworth T L, Lu J, Findell K L and Knutson T R.
2005. Simulation of Sahel drought in the 20th and 21st centuries.
PNAS. 105(50): 17 891–6.
Idso S B, Kimball B A, Pettit III G R, Garner L C, Pettit G R
and Backhaus R A. 2000. Effects of atmospheric CO2
enrichment on the growth and development of Hymenocallis
littoralis (Amaryllidaceae) and the concentration of several
antineoplastic and antiviral constituents of its bulbs. American
Journal of Botany 87: 769–73.
Intergovernmental Panel on Climate Change. 2007. Climate
Change 2007: Synthesis Report. November 2007 available at:
http://www.ipcc.ch/ pdf/assessment-report/ar4/syr/
ar4_syr.pdf.
Kirdmanee C, Kitaya Y and Kozai T. 1995. Effects of CO2
enrichment and supporting material in vitro on
photoautorophic growth of Eucalyptus plantlets in vitro and
ex vitro. In Vitro Cellular and Developmental Biology-Plant
31(3): 144–9.
Law W and Salick J. 2005. Human-induced dwarfing of
Himalayan snow lotus, Saussurea laniceps (Asteraceae). PNAS
102(29): 10 218–20.
Lindzen R S. 1990. Some coolness concerning global warming.
Bull. Amer. Meteorol. Soc. 71: 288–99.
Parmesan C and Yohe G. 2003. A globally coherent fingerprint of
climate change impacts across natural systems. Nature 421:
37–42.
Malcolm J R, Liu C, Neilson R P, Hansen L and Hannah L.
2006. Global warming and extinctions of endemic species from
biodiversity hotspots. Conservation Biology 20(2): 538–48.
Marshall Elizabeth, Aillery Marcel, Malcolm Scott and Williams
Ryan. 2015. Agricultural Production under Climate Change:
The potential impacts of shifting regional water balances in
the united states. American Journal of Agricultural Economics
97(2): 568–88.
Neilson R P, Pitelka L F and Solomon A M, 2005. Forecasting
regional to global plant migration in response to climate change.
Bio Science 55(9): 749–59.
Nickens T E. 2007. Walden warming. National Wildlife. October/
November: 36–41.
Pal J S, Giorgi F and Bi X. 2004. Consistency of recent European
summer precipitation trends and extremes with future
regional climate projections. Geophysics Research Letters 31:
L13202.
Pompe S, Hanspach J, Badeck F, Klotz S, Thuiller W and Kuhn
I. 2008. Climate and land use change impacts on plant
distributions in Germany. Biology Letters 4: 564–7.
Schar C, Vidale P L and Luthi D. 2004. The role of increasing

1382 [Indian Journal of Agricultural Sciences 86 (11)
10
DAS ET AL.
temperature variability in European summer heatwaves. Nature
427: 332–6.
Seon J H, Cui C H, Paek Ky, Yang C S, Gao W Y, Park C H and
Sung S N. 1995. Effects of air exchange, sucrose, and ppf on
growth of rehmannia glutinosa under enriched CO2
concentration in vitro. In Vitro Cellular and Developmental
Biology-Plant, 31(3):151-156.
Shea J. 2008. Apple growers hopeful after freeze. Times-News. 6
April.
Stuhlfauth T and Fock H P. 1990. Effect of whole season CO2
enrichment on the cultivation of a medicinal plant, Digitalis
lanata. Journal of Agronomy and Crop Science 164: 168–73.
Stuhlfauth T, Klug K and Fock H P. 1987. The production of
secondary metabolities by Digitalis lanata during CO2
enrichment and water stress. Phytochemistry 26: 2 735–9.
Tack Jesse, Barkley Andrew and Nalley Lawton Lanier. 2015.
Estimating yield gaps with limited data: An application to
United States Wheat. American Journal of Agricultural
Economics 97(3): 42–51.
Thomas C D, Cameron A and Green R E. 2004. Extinction risk
from climate change. Nature 427: 145–8.
Walther G R, Post E, and Convey P. 2002. Ecological responses
to recent climate change. Nature 416: 389–95.
World Health Organization. 2002. Traditional medicine: Growing
needs and potential. WHO Policy Perspectives on Medicines
2: 1–6.
Yoon C K. 1994. Warming moves plants up peaks, threatening
extinction. New York Times. June 21, C4.
Ziska L H. 2005. The impact of recent increases in atmospheric
CO2 on biomass production and vegetative retention of
Cheatgrass (Bromus tectorum): Implications for fire
disturbance. Global Change Biology 11: 1 325–32.
Zobayed S M A, Afreen F and Kozai T. 2005. Temperature
stress can alter the photosynthetic efficiency and secondary
metabolite concentrations in St. John’s wort. Plant Physiology
and Biochemistry 43: 977–84.