Impatti regionali dei cambiamenti climatici globali sugli ecosistemi: un'analisi del caso della Lombardia
←
→
Trascrizione del contenuto della pagina
Se il tuo browser non visualizza correttamente la pagina, ti preghiamo di leggere il contenuto della pagina quaggiù
Impatti regionali dei cambiamenti climatici globali sugli ecosistemi: un’analisi
del caso della Lombardia
Marino Gattoa, Giulia Fioresea, b, Giulio De Leob
a
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Via Ponzio 34/5, 20133 Milano, Italia
b
Dipartimento di Scienze Ambientali, Università degli Studi di Parma, Viale Usberti 11/A, 43100 Parma, Italia
Il clima terrestre sta modificandosi ad una velocità senza precedenti per cause non solo naturali,
bensì principalmente antropogeniche. Il recente rapporto dell’IPCC pubblicato all’inizio del 2007
non lascia dubbi sulle responsabilità umane nel provocare i cambiamenti climatici: “L’incremento
globale della concentrazione di biossido di carbonio è principalmente dovuto all’uso di combustibili
fossili e ai cambiamenti nell’utilizzo dei suoli, mentre gli incrementi di metano e ossido di azoto
sono principalmente dovuti all’agricoltura”. L’aumento della temperatura registrato nell’ultimo
secolo (1906-2005) è, secondo le più recenti misure, di 0,74°C, in aumento rispetto allo 0,6°C del
periodo 1901-2000. Dal 1950 in poi, ogni dieci anni la temperatura è aumentata in media di 0,13°C.
Nei prossimi 20 anni, gli scenari di emissioni SRES e le proiezioni dei modelli climatici prevedono
un riscaldamento compreso tra 1,8 e 4°C nel 2099, rispetto al periodo 1980-1999. Si assisterà,
dunque, ad un ulteriore aumento della temperatura e dei fenomeni generalmente ascritti ai
cambiamenti climatici, ad esempio: variazione delle precipitazioni con un aumento dell’intensità di
pioggia; aumento di fenomeni quali piene in autunno o inverno, siccità in primavera ed estate,
ondate di calore, incendi. Queste variazioni del clima e della temperatura hanno già notevoli impatti
sul sistema socio-economico ed ecologico globale e, quindi, anche dell’Italia. È necessario che
siano intraprese serie politiche mitigative, come quella lanciata nel marzo 2007 dalla Commissione
Europea per la riduzione delle emissioni e l’aumento del contributo delle fonti rinnovabili al 2020.
Gli effetti dei cambiamenti climatici sui sistemi naturali sono molteplici: il clima è uno dei fattori
che ne determinano la composizione, la produttività e la struttura. Molte specie possono riprodursi e
svilupparsi con successo solo all’interno di un determinato intervallo di temperature e di
precipitazioni; analogamente, le condizioni meteo-climatiche influiscono sulla distribuzione
geografica delle specie, a cui, però, si deve aggiungere la disponibilità di risorse alimentari. I
cambiamenti climatici possono di conseguenza modificare direttamente (ad es. tramite l’aumento
della temperatura) o indirettamente (ad es. tramite la modifica della disponibilità di cibo per le
specie animali) gli ecosistemi, nonché gli individui e le popolazioni che li abitano.
Impatti diretti possono avvenire sulla struttura e il funzionamento degli ecosistemi terrestri, sulla
fisiologia e fenologia delle specie vegetali e animali, sulla localizzazione degli areali di
distribuzione delle specie. Negli ecosistemi acquatici gli impatti sono causati principalmente
dall’aumento della temperatura dell’acqua e dalla variazione del regime idrico. Impatti indiretti
sono dovuti, invece, all’interazione tra le specie, alla variazione della biodiversità, all’invasione di
specie alloctone, alla diffusione di vettori di malattie e di agenti infestanti negli ecosistemi. Un
importante e complesso impatto indiretto è il disaccoppiamento di eventi sincroni: la risposta
individuale delle specie ai cambiamenti climatici può alterare le interazioni tra specie diverse, allo
stesso livello trofico o a livelli adiacenti. Quando specie che interagiscono o competono tra di loro
mostrano risposte divergenti, il risultato della loro interazione può modificarsi radicalmente.
L’analisi preliminare svolta nell’ambito del Progetto Kyoto Lombardia mostra che le aree più
vulnerabili della Lombardia sono quelle isolate, localizzate ad esempio in zone montane con scarse
possibilità per le specie di spostarsi seguendo il clima a loro più adatto. Le specie ittiche sono
vulnerabili in quanto lo spostamento degli individui è ostacolato dalla presenza di numerose
barriere di origine antropica che interrompono e dividono il corso del fiume. Il territorio della
Lombardia, inoltre, è già soggetto a numerose pressioni (uso del suolo, inquinamento del suolo,
dell’acque e dell’aria) a cui si devono sommare le pressioni dovute ai cambiamenti climatici; queste
pressioni aggravano gli impatti dei cambiamenti climatici poiché diminuiscono la capacità di
adattamento dei sistemi naturali e delle specie che li compongono.
1Regional impacts of global climate change on ecosystems: an analysis of the
Lombardy (northern Italy) case
Marino Gattoa, Giulia Fioresea, b, Giulio De Leob
a
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Via Ponzio 34/5, 20133 Milano, Italia
b
Dipartimento di Scienze Ambientali, Università degli Studi di Parma, Viale Usberti 11/A, 43100 Parma, Italia
1. Introduction
The Earth’s climate is changing at an unprecedented rate and, moreover, changes are not mainly
driven by natural variations, rather by anthropogenic causes. The recently released
Intergovernmental Panel of Climate Change (IPCC) Summary on the Physical Science Basis of
global climate change (IPCC, 2007a), leaves no doubt about our responsibilities in causing climate
change: “the global increases in carbon dioxide concentration are due primarily to fossil fuel use
and land-use change, while those of methane and nitrous oxide are primarily due to agriculture”.
Carbon dioxide (CO2) atmospheric concentration has increased from a pre-industrial value of about
280 ppmv to 381 ppmv in 2006, which is the highest concentration in the past 650,000 years
(Siegenthaler et al., 2006). In the last decade an exceptional increase of 1.9 ppmv per year has been
experienced (IPCC, 2007a).
The 2007 IPCC report shows that the average surface temperature of the Earth increased more than
projected in the 2001 Third Assessment Report (TAR; IPCC, 2001): the 1906-2005 linear trend
indicates a temperature increase of 0.74±0.18°C, which is larger than the corresponding trend of
0.6±0.2°C for 1901-2000 (IPCC, 2001). The 8 warmest years recorded since 1680, when
instrumental measures of temperature became available, occurred in the last 14 years and 2005 has
been the warmest year ever. Europe is experiencing even higher rates of temperature increase:
0.95°C versus 0.74°C (EEA, 2004).
The detection of global and regional trends for precipitation is more difficult because precipitation
regimes are inherently stochastic and strongly depend on local climatic and morphological
characteristics. Nonetheless, improvement in data analysis and modelling have been made and,
according to the IPCC report (2007a), significant precipitation increase has been observed in eastern
parts of North and South America, in northern Europe and in northern and central Asia. Drying has
been observed in the Sahel, the Mediterranean, southern Africa and parts of southern Asia.
In accordance with these trends, climate in Italy has been changing in the past century with
temperature increasing of about 1°C (Figure 1). In the last 50 years, the increase of maximum
temperature has been stronger than that of minimum temperature (whilst in the first part of the 20th
century, the trend was opposite), thus leading to a positive trend in the daily temperature range
(Brunetti et al., 2006). In the last two centuries, precipitation showed a decreasing tendency: there is
a 5% negative trend per century in the annual amount of precipitation, mainly due to a 9% decrease
in spring (Brunetti et al., 2006).
If we focus on the Alpine region, an extremely vulnerable ecosystem, a recent study (Auer et al.,
2007) estimates a 1.0-1.4°C temperature increase in the 20th century; in Switzerland minimum
temperatures increased up to 2°C, while maximum temperature showed a smaller increase
(Beniston, 2005). Looking at the past century, the greatest rate of increase has been observed since
1970-1980. Mountainous regions, like the Alps, are particularly vulnerable to climate change and
are already suffering from higher than average increases in temperature, as shown in Figure 2
(Beniston, 2005). Unlike temperature, precipitation does not show a clear trend in the past century.
On the other hand, significant regional and seasonal differences have been observed throughout the
Alpine region with a 9% increase in the North West and a 9% decrease in the South East (Auer et
al., 2007).
2Figure 1: Italian mean temperature series, deviation from the 1961-1990 mean (Brunetti, 2007).
2. Impacts of global climate change
Global climate change (GCC) impacts are already apparent on large scale and on a variety of
sectors: from society and economy, to agriculture and ecosystems. Table 1 shows some of the main
dangerous impacts expected as consequences of GCC, with their respective probability estimates.
In the framework of the Kyoto Lombardia project1, we have analyzed GCC impacts on Lombardy,
the largest, most industrialized and economically important region of northern Italy (De Leo et al.,
2006). Direct impacts are mainly driven by the increased frequency of extremes, mainly heat waves
and heavy precipitation. Lombardy is subject to a variety of these impacts and, with the increasing
intensity of GCC, its vulnerability will increase. Lombardy is characterized by a wide variety of
natural environments that encompass the Alpine region, the Apennines, the river Po Valley,
numerous rivers and large hydrological basins. Moreover, impacts will overlap and interact with
structural elements that characterize the regional socio-economic and natural characteristics: high
population density, high percentage of elderly people, intensive land use and widespread
urbanization, increasing energy demand, richness of the artistic heritage, hydrological instability,
large agricultural production, high biodiversity and a network of protected natural areas.
With temperatures 4°C above the season average for 3 consecutive months, the 2003 heat wave
caused 7,000 deaths in Italy (see Conti et al., 2005, and EpiCentro, 2007). Other European regions
experienced similar events (EEA, 2004). These events will become more frequent with increasing
atmospheric temperatures and their impact will be worst in urban areas, where the urban heat island
effect adds up. Heat waves and the overall temperature rise will cause an increase in air
conditioning use, and, thus, in electrical energy demand; this may lead to a higher risk of black-
outs. To understand consequences of black-outs, just consider that 2003 summer black-outs caused
economical damages to the Italian industrial sector amounting to about 400 million euros.
Another GCC direct impact which is already remarkable is the melting of Alpine glaciers, a
phenomenon going on for several decades. Snow cover is also decreasing, thus diminishing the
amount of water that is stored in the snow pack. The combination of these two events does alter the
hydrological regime, affecting both the timing of dams filling and the water supply for agricultural
or industrial purposes. In Lombardy, 28% of electric power demand is satisfied by hydropower
(GRTN, 2006); moreover, Lombardy is one of Italy’s most productive regions in terms of industry
and agriculture, both water demanding activities. Thus, the alteration of the hydrological pattern has
the potential to seriously affect the regional productive system. Figure 3 shows the changes of
seasonal runoff (water from rain or snowmelt that flows off the land) expected for the end of current
century in the Central Alps: a 90% increase in the winter and a 45% decrease in the summer, which
will imply a corresponding increased risk of floods and droughts (Beniston, 2006; EEA, 2007a).
Also, runoff directly affects debris flow and soil erosion.
1
www.kyotolombardia.org
3Figure 2: Temperature departures from the 1961–
1990 climatological mean in the Swiss Alps compared Figure 3: Change in seasonal run-off in the central
to global temperature anomalies, for the period 1901– Alps in 2071–2100 compared with 1961–1990
2000 (Beniston, 2005). (Beniston, 2006; EEA, 2007a).
Table 1: Projected effects of global warming during the 21st Century (IPCC, 2007b).
Projected Effect Examples of Projected Impacts with high confidence of occurrence
Over most land areas, warmer and Increased yields in colder environments; decreased yields in warmer
fewer cold days and nights, warmer environments; increased insect outbreaks.
and more frequent hot days and nights. Effects on water resources relying on snow melt; effects on some water
supply.
Virtually certain Reduced human mortality from decreased cold exposure.
(>99% probability of occurrence) Reduced energy demand for heating; increased demand for cooling; declining
air quality in cities; reduced disruption to transport due to snow, ice; effects
on winter tourism.
Warm spells/heat waves. Frequency Reduced yields in warmer regions due to heat stress; wild fire danger
increases over most land areas. increase.
Increased water demand; water quality problems, e.g., algal blooms.
Very likely Increased risk of heat-related mortality, especially for the elderly, chronically
(90 to 99% of probability) sick, very young and socially isolated.
Reduction in quality of life for people in warm areas without appropriate
housing; impacts on elderly, very young and poor.
Heavy precipitation events. Frequency Damage to crops; soil erosion, inability to cultivate land due to water logging
increases over most areas. of soils.
Adverse effects on quality of surface and groundwater; contamination of
Very likely water supply; water scarcity may be relieved.
(90 to 99% of probability) Increased risk of deaths, injuries, infectious, respiratory and skin diseases.
Disruption of settlements, commerce, transport and societies due to flooding;
pressures on urban and rural infrastructures; loss of property.
Area affected by drought increases. Land degradation, lower yields/crop damage and failure; increased livestock
deaths; increased risk of wildfire.
Likely More widespread water stress.
(66 to 90% of probability) Increased risk of food and water shortage; increased risk of malnutrition;
increased risk of water- and food-borne diseases.
Water shortages for settlements, industry and societies; reduced hydropower
generation potentials; potential for population migration.
Impacts of temperature rise on snow cover, glaciers and permafrost are likely to have adverse
effects on winter tourism, leading to economic losses. Italian ski areas are mainly located at high
altitudes, where there is a fairly high natural-snow reliability (the snow-reliability line is estimated
to be at about 1,500 m asl). If the snow line were to move upwards by 300 m (plus 2°C by 2050),
the percentage of ski areas relying on natural snow in the Lombardy Alps would decrease by 17%
(OECD, 2007).
The Lombardy territory is strongly characterised by a high flood risk and hydro-geologic instability
like many other parts of the Italian territory: more than 7,700 km2 of the country is considered at
risk of flood. In the past 30 years, Italy has been the first European country for number of victims
and the second country, after France, for number of extreme events. According to the European
4Environment Agency, since 1990 the number of extremes in Europe has doubled and the average
annual damage has increased from 5 to 11 billion euros. Among extreme weather events, floods
cover a main role. Every year they represent 1/3 of total events, cause half of the total deaths and
account for 1/3 of the total economic damage (EEA, 2004; EEA, 2003; Munich Re, 2000). It is
estimated that storms and landslides in all the Alpine region generated economic losses of 57 billion
euros over the 1982-2005 period (OECD, 2007). The decrease of rainfall in late winter may
increase the risk of forest fires; extended droughts negatively impact on crop yields, while water
scarcity can trigger and increase conflicts on water use between agriculture and hydropower sectors.
3. Focusing on ecosystems
There are numerous GCC impacts on natural biological systems: climate is in fact one of the factors
that determines ecosystems’ composition, productivity and structure. Several plants can
successfully grow and reproduce in a specific range of temperatures and precipitation regimes.
Meteoclimatic conditions, together with food resources availability, affect fauna’s geographical
distributions. Regional climate is one of the factors that influences species geographical
distributions through physiological tolerance thresholds, e.g., of temperature and rainfall. Biota with
narrow physiological and phenological ranges will be the most vulnerable to climate change.
Climate change can affect ecosystems, populations and individuals directly (e.g., through rising
average temperature) or indirectly (e.g., through changes in food resources availability). Impacts
imply changes in the structure and functioning of ecosystems, in the physiology and phenology of
plant and animal species, in their range distribution. Some of the pathways through which GCC can
affect ecosystems are shown in Figure 4, where arrows show the numerous links and relations
existing within the different parts that constitute ecosystems. Figure 4 is a representation of impacts
on plant species in terrestrial ecosystem; similar charts can be drawn for animal species and for
aquatic ecosystems as well.
Figure 4: Web-chart of climate change impacts on plant species in terrestrial ecosystems (De Leo et al.,
2006).
5A major negative impact is given by the increased frequency of extreme events (e.g., heat waves,
droughts, storms), that directly affects ecosystems; at the same time, small, continuing and
progressive variations of temperature and of other climate drivers are able to affect the biological
cycle of many species. Mild winters can affect the competitive interactions existing within the
species, altering the structure of the biological community and, in some case, enabling the spread of
pathogens that would be otherwise killed during winter (Harvell et al., 2002).
The atmospheric increase in carbon dioxide can have a fertilizing effect on vegetation, through the
increase of photosynthetic activity and a more efficient use of water resources. Enhanced plant
biomass accumulation in response to elevated atmospheric CO2 concentration could dampen the
future rate of increase in CO2 levels and associated climate warming. However, it is unknown
whether CO2-induced stimulation of plant growth and biomass accumulation will be sustained or
whether limited nitrogen (N) availability constrains even more plant growth in a CO2-enriched
world. In fact, a recent study (Reich et al., 2006) of perennial grassland species grown under
ambient and elevated levels of CO2 and N, showed that low availability of N progressively
suppresses the positive response of plant biomass to elevated CO2. Given that limitations to
productivity resulting from the insufficient availability of N are widespread in both unmanaged and
managed vegetation, soil N supply is probably an important constraint on global terrestrial
responses to elevated CO2.
Temperature directly affects primary productivity and, thus, the carbon cycle, through changes in
carbon stored in plants, soils and partially emitted through respiration. Other direct consequences of
rising temperatures, of minimum temperatures above all, on vegetation is the advance of the
growing and flowering seasons, and the delay in leaf colouring and fall in autumn. From 1962 to
1996, the growing season in Europe extended its duration of about 10 days: spring now begins
about 6 days earlier than 50 years ago, while the end of autumn is delayed by 4.8 days (EEA, 2004;
Menzel and Fabian, 1999). Recent evidence of plants’ phenological adaptation to GCC are reported
in Menzel et al. (2006). Future climate warming is generally expected to enhance plant growth in
temperate ecosystems and to increase carbon sequestration. However, this may not be true under
any condition. The heat wave of 2003 provided ecologists with a very unique opportunity to
measure primary production of European ecosystems under an extreme climate stress (Ciais et al.,
2005). It has been estimated that there was a 30 per cent reduction in gross primary productivity
over Europe, which resulted in a strong anomalous net source of carbon dioxide (0.5 PgC yr-1) to
the atmosphere and reversed the effect of four years of net ecosystem carbon sequestration. On the
other hand, ecosystem respiration decreased together with gross primary productivity, rather than
accelerating with the temperature rise. Thus, an increase in future drought events could turn
temperate ecosystems into carbon sources, contributing to positive carbon-climate feedbacks
already anticipated in the tropics and at high latitudes
Phenological changes have been observed for animal species too, typically as an earlier timing in
migration, reproduction and emergence from larval stages (Root and Schneider, 2002; Walther et
al., 2002). Changes in meteo-climatic conditions also affect growth, fertility, and mortality rates
that characterise animal populations. For example, the survival rate of several bird species (grey
heron, common buzzard, cormorant, song thrush, redwing) has increased by 2-6% for each degree
of rising temperature; birds living in northern Europe are thus benefiting from raising temperatures
(EEA, 2004).
One of the main consequences of climate change is that geographic ranges of some plants and
animals will shift upward in elevation (e.g., alpine vegetation; GLORIA, 2007) and northward (e.g.,
the ranges of several butterfly species in Europe; Parmesan et al., 1999). Such major shifts in
species’ locations alter species’ interactions and potentially threaten biodiversity. The increasing
temperature will reduce the availability of suitable habitat and will move species towards higher
elevations or latitudes. Vulnerable species at risk of losing their habitat are those with limited
distribution ranges, with narrow tolerance ranges and endemic species on mountain tops, where
there is no space to shift upwards. In mountain areas, habitats are already fragmented and
6surrounded by land altered by man’s use; natural and human barriers will likely obstacle species
migration toward more suitable habitats, in the attempt of following climate changes. On the high
peaks of the European Alps, Pauli et al. (2006) have detected an ongoing range contraction of
subnival to nival species at the lower edge and a concurrent expansion of alpine pioneer species at
the leading edge of their geographic range. This results in a transitory increase of biodiversity at
certain elevations, given by the development of spruce and pines in the sub-alpine region and of
sub-alpine shrubs closer to the mountain peak. Endemic mountain species might be thus threatened
by sub-alpine shifts of shrubs and tree species driven by GCC. Parolo and Rossi (2007) found
similar results for vascular plants in the Rhaetian Alps.
Climate change can also affect distribution ranges of pests or pathogens, and their rates of
transmission (Harvell et al., 2002). This can possibly affect human health, increasing the risk of
contracting infections, and agriculture, increasing the risk of pests spread. Pests and diseases can
also impact on natural systems such as woods and the wildlife. For example, ticks can transmit a
variety of diseases, such as tick-borne encephalitis (TBE) and Lyme disease (in Europe called Lyme
borreliosis). Both diseases are not lethal, but can seriously affect human health. TBE in the past was
considered a local disease in a few nations: the altitudinal limit extends up to 2,000 m in southern
Europe, 1,300 m in the Italian Alps and 700 m in the mountainous areas of central Europe. Because
of milder temperatures and favourable humidity conditions, ticks are now extending their
distribution; observations come from the Baltic and the central European countries (Lindgren et al.,
2000). It is not clear yet how many of the 85,000 cases of Lyme borreliosis reported annually in
Europe are attributable to temperature increases over the past decades rather than to deer host
expansion and land use change (EEA, 2004).
Changes in behaviour and abundance and the local loss or invasion of species will change the
structure and the functioning of ecosystems, which in turn may lead to other species loss and other
negative impacts. Moreover species will react differently to climate change, causing a mismatch
within different component of the ecosystem (Stenseth et al., 2002). This non-linear impacts are
difficult to assess but greater and greater evidence is accumulating especially for avian predators
feeding on insects. For example Visser et al. (1998) observed the following interaction between
species’ reproductive timing and food availability. The great tit (Parus major) tends to lay eggs in
advance, in response to the earlier spring arrival; larvae, a primary food resource, on the other hand,
do not shift their peak abundance in accordance to spring advance, showing no response to rising
temperature. This leads to an asynchrony in food availability for great tits’ chicks: because of
different timing in response to GCC, larvae are not available when birds energetic demand are
highest. The population consequences of this mistiming has been recently assessed by Both et al.
(2006) with reference to the migratory pied flycatcher (Ficedula hypoleuca). In a comparison of
nine Dutch populations, they found that populations have declined by about 90% over the past two
decades in areas where the food for provisioning nestlings peaks early in the season and the birds
are currently mistimed.
Direct impacts are observed on aquatic ecosystems as well; these are mainly driven by water
temperature increase and by changes in water flows (reduced summer flows are critical, because
there is a synergism between higher atmospheric temperature and the smaller heat capacity of
reduced water volumes). Rivers in Lombardy are disseminated with several human constructions
and waterworks(e.g., to regulate river flows and avoid floods and to provide water for agriculture
and electric power production). These constructions will hamper the species movements, while they
attempt to track changes in climate.
Changes of spatial distribution and population decline have already been observed, for example, in
Switzerland for the brown trout (Salmo trutta). Hari et al. (2006) showed that the decrease of trout
catch from 907 to 484 individuals per kilometre of river is connected to the increase of temperature.
A concurrent cause of brown trout decline is attributed to the diffusion of the proliferative kidney
disease (PKD) since the beginning of the 1970’s. Originally, PKD was found up to 400 m altitudes,
7but it has been spreading to higher altitudes, up to 800 m, as a consequence of water temperature
increase.
4. Impacts on alpine ibex: a case study
A preliminary analysis on the charismatic alpine ibex (Capra ibex ibex) was carried out for Parco
dell’Adamello (Fiorese et al., 2005), a national park located in Lombardy. The importance of the
Parco dell'Adamello is due to its position: with the four parks with which it borders, the total
protected area amounts to 250,000 ha, one of the biggest in Europe. Furthermore, ibex was on the
verge of extinction at the end of the 19th century and is now recovering. Between 1994 and 1997
and since 2000, re-introduction operations were carried out in Parco dell’Adamello; knowing how
ibex will respond to climate change is important in order to predict the success of this
reintroduction.
To this end we have used and adapted a specific habitat suitability model developed for the ibex by
Pedrotti and Tosi (1996). The ibex habitat suitability model consists of two submodels: one for the
winter and one for the summer. The winter model depends, via discrete functions, upon altitude,
exposition, slope and vegetation type; the aestivation model depends on altitude only. In order to
estimate climate change impacts on
habitat suitability, altitude is
Table 2: Average temperature increases in winter and summer seasons considered as a proxy for
for A2 and B2 scenarios in 2020 and 2050; increases are simulated by
temperature.
HadCM3 model for Northern Italy cell.
We considered two climate change
Winter 2020 Summer 2020 Winter 2050 Summer 2050 emission scenarios among those
(°C) (°C) (°C) (°C)
0.84 2.39 2.02 4.83
proposed by IPCC, the so-called
A2
B2 1.54 3.08 1.82 4.42 SRES scenarios A2 and B2. They
correspond to different storylines
that lead to future (2100) high and
low CO2 concentrations, 1,250 (A2) and 800 ppmv (B2), respectively. The monthly average
increase of temperature (with respect to 1961-1990) in the cell of Northern Italy was taken from the
simulations made by the Hadley Center HadCM3 model for 2020 (short term scenario) and 2050
(medium term scenario). We considered as reference period 1979-1990 because of the availability
of monthly temperature series recorded in a meteorological station close to the Parco
dell’Adamello. The increase of temperature in winter and summer is shown in Table 2.
Under the hypothesis that temperature varies with elevation according to a moist adiabatic lapse
rate, the ibex altitudinal ranges were re-calculated for the temperature increases of A2 and B2
scenarios in 2020 and in 2050. As temperature rises, suitable altitudinal ranges shift to higher
elevations.
Results of the analysis clearly show that ibex population distribution and abundance in Parco
dell’Adamello will be affected by climate change. Precisely, because of the projected increase of
average temperature, the population potential density will slightly increase in the winter and
strongly decrease in the summer. Figure 5 shows the suitability maps obtained as output of the
winter and summer models for the A2 scenario in 2020 and 2050. A marked contraction of the 2020
suitable area is observed, with a further worsening in 2050. In future scenarios, the suitable area
shifts toward the Eastern side of the Parco dell’Adamello, where the highest elevations are located.
A similar result is obtained for the B2 scenario.
In the summer, ibex potential density in Parco dell’Adamello decreases from 1,511 individuals to
891 in the best situation (A2 – 2020) down to 380 in the worst situation (A2 – 2050); in the winter,
potential density increases from 1,587 to 1,777 in the best situation (A2 – 2050) and to 1,684 in the
worst situation (A2 – 2020). The critical season is thus summer: the availability of suitable areas in
this season will act as a bottleneck for the overall ibex population in the Parco dell’Adamello.
8a) b) c) d)
Figure 5: Comparison between ibex habitat suitability maps for winter (a, b) and summer (c, d) models in Parco
dell’Adamello; with respect to current suitability, in future scenarios areas in yellow remain suitable, areas in pink are
lost and areas in blue are gained. a) A2 – 2020 scenario; b) A2 – 2050 scenario; c) A2 – 2020 scenario; d) A2 – 2050.
5. Conclusion
The latest Assessment Report of the IPCC (2007a) projects that global average temperatures in
2100 will be between 1.8–4.0 °C higher than the 1980–2000 average (likely range 1.1–6.4 °C). Sea
levels are projected to rise 0.18–0.59 m by 2100. More frequent and intense extreme weather events
(including droughts and flooding) are also expected.
The need to mitigate climate change and prevent dangerous impacts has resulted in a strong
European policy committment to the reduction of greenhouse gas emissions. The EU set the target
to limit temperature increase to 2°C above pre-industrial levels to limit dangerous climate change.
In order to be able to reach this target, in March 2007 the European Commission decided to
implement an extremely important policy, taking the lead to the climate change global challenge
(European Commission, 2007). The renewable energies roadmap sets a target of 20% for the share
of total energy consumption to come from renewable sources by 2020 (the current share is 6.5%).
This increase will contribute to reducing the European Union's total emissions of greenhouse gases.
A 20% reduction of greenhouse gases is, according to the EU commission, the minimum required to
achieve the goal of limiting the increase of global temperatures to 2°C.
The 2010 Kyoto Protocol commitment is getting close and Italy is far from the fixed target. Italian
greenhouse gases emissions have been increasing, instead of decreasing. Italy has undertaken the
commitment to reduce overall national emissions by 6.5% with respect to the base-year by 2008–
2012. However, the total emissions in 2004, in CO2-equivalent terms, are 9.9% higher than the
base-year (EEA, 2007b). Adaptation and mitigation policies are needed in order to reduce
greenhouse gases emissions and to limit impacts on our environment, society and economy.
Acknowledgements
The research has been supported by Fondazione Lombardia per l’Ambiente and Regione Lombardia
(Progetto Kyoto Lombardia), and by Ministero dell’Università e della Ricerca (Progetto Interlink
II04CE49G8).
References
Auer I, R Böhm, A Jurkovic, W Lipa, A Orlik, R Potzmann, W Schöner, M Ungersböck, C Matulla, K Briffa
et al. (2007). HISTALP - historical instrumental climatological surface time series of the Greater Alpine
Region, International Journal of Climatology 27(1): 17-46.
9Beniston M (2005). Mountain Climates and Climatic Change: An Overview of Processes Focusing on the
European Alps, Pure and Applied Geophysics 162(8): 1587-1606.
Beniston M (2006). Climatic change in the Alps, Workshop Adaptation to the Impacts of Climatic Change in
the European Alps, Wengen, October 4-6. Available at http://www.oecd.org/dataoecd/1/13/37805798.pdf.
Both C, S Bouwhuis, CM Lessells, ME Visser (2006). Climate change and population declines in a long-
distance migratory bird, Nature 441: 81-83.
Brunetti M (2007). http://www.isac.cnr.it/~climstor/climate_news.html, last visited February 2007.
Brunetti M, M Maugeri, F Monti, T Nanni (2006). Temperature and precipitation variability in Italy in the
last two centuries from homogenised instrumental time series, International Journal of Climatology 26(3):
345-381.
Ciais Ph, M Reichstein, N Viovy, A Granier, J Ogée, V Allard, M Aubinet, N Buchmann, Chr Bernhofer, A
Carrara et al. (2005). Europe-wide reduction in primary productivity caused by the heat and drought in 2003,
Nature 437: 529-533.
Conti S, P Meli, G Minelli, R Solimini, V Toccaceli, M Vichi, C Beltrano, L Perini (2005). Epidemiologic
study of mortality during the Summer 2003 heat wave in Italy, Environmental Research 98: 390–399.
De Leo G, M Gatto, G Fiorese, D Bevacqua, L Bolzoni, M Fornari, M Parelli (2006). Quadro sinottico degli
impatti dei cambiamenti climatici globali sulla regione Lombardia, Progetto Kyoto Lombardia, Milano.
EEA (2003). Mapping the impacts of recent natural disasters and technological accidents in Europe,
N34/20036, Copenhagen.
EEA (2004). Impacts of Europe’s changing climate. An indicator-based assessment. N2/2004, Copenhagen.
EEA (2007a). Climate change and water adaptation issues, Technical report 2/2007.
EEA (2007b). Greenhouse gas emissions and removals (CSI 10) – Assessment published February 2007,
http://themes.eea.europa.eu/IMS/CSI, last visited April 2007.
EpiCentro – Centro Nazionale di Epidemiologia, Sorveglianza e Promozione della Salute (2007),
www.epicentro.iss.it, last visited April 2007.
European Commission (2007). http://europa.eu/press_room/presspacks/energy/index_en.htm, last visited
March 2007.
Fiorese G, M Gatto, G Ranci Ortigosa, G De Leo (2005). Scenari futuri di impatto dei cambiamenti climatici
globali tramite l’applicazione di modelli di vocazionalità faunistica a ungulati alpini, Atti del XV Congresso
della Società Italiana di Ecologia, Torino September 12-14.
GLORIA (2007). The global observation research initiative in alpine environments, http://www.gloria.ac.at/,
last visited March 2007.
GRTN (2006). Statistiche sulle fonti rinnovabili in Italia – anno 2005, www.grtn.it, last visited April 2007.
Hari RE, DM Livingstone, R Siber, P Burkhardt-Holm, H Güttinger (2006). Consequences of climatic
change for water temperature and brown trout populations in Alpine rivers and streams, Global Change
Biology 12(1): 10-26.
Harvell CD, CE Mitchell, JR Ward, S Altizer, AP Dobson, RS Ostfeld, MD Samuel (2002). Climate
warming and disease risks for terrestrial and marine biota, Science 296: 2158-2162.
IPCC (2001). Climate change 2001: The scientific basis, Cambridge University Press, Cambridge, UK.
IPCC (2007a). Climate Change 2007: The physical science basis, Summary for Policymakers, Cambridge
University Press, Cambridge, UK.
IPCC (2007b). Climate Change 2007: Impacts, adaptation and vulnerability, Summary for Policymakers,
Cambridge University Press, Cambridge, UK.
Lindgren E, L Talleklint, T Polfeldt (2000). Impact of climatic change on the northern latitude limit and
population density of the disease-transmitting European tick, Ixodes ricinus, Environmental Health
Perspectives 108(2): 119-123.
10Menzel A, P Fabian (1999). Growing season extended in Europe, Nature 397: 659.
Menzel A, TH Sparks, N Estrella, E Koch, A Aasa, R Ahas, K Alm-Kübler, P Bissolli, O Braslavská, A
Briede et al. (2006). European phenological response to climate change matches the warming pattern, Global
Change Biology 12(10): 1969-1976.
Munich Re (2000). Topics-annual Review of Natural Disasters 1999, Munich Reinsurance Group, Munich,
Germany.
OECD (2007). Climate Change in the European Alps: Adapting Winter Tourism and Natural Hazards
Management, ed. Shardul Agrawala, Paris, France.
Parmesan C, N Ryrholm, C Stefanescu, JK Hill, CD Thomas, H Descimon, B Huntley, L Kaila, J Kullberg,
T Tammaru et al. (1999). Poleward shifts in geographical ranges of butterfly species associated with regional
warming, Nature 399: 579-583
Parolo G, G Rossi (2007). Upward migration of vascular plants following a climate warming trend in the
Alps, Basic and Applied Ecology, doi:10.1016/j.baae.2007.01.005.
Pauli H, M Gottfried, K Reiter, C Klettner, G Grabherr (2006). Signals of range expansions and contractions
of vascular plants in the high Alps: observations (1994–2004) at the GLORIA master site Schrankogel,
Tyrol, Austria, Global Change Biology 13(1): 147-156.
Pedrotti L, G Tosi (1996). Progetto Stambecco Adamello. Studio di fattibilità e progettazione, Regione
Lombardia, Servizio tutela ambiente naturale e parchi.
Reich PB, SE Hobbie, T Lee, DS Ellsworth, JB West, D Tilman, JMH Knops, S Naeem, J Trost (2006).
Nitrogen limitation constrains sustainability of ecosystem response to CO2, Nature 440: 922-925.
Root TL, SH Schneider (2002). Climate change: overview and implications for wildlife in Wildlife
Responses to Climate Change: North American Case Studies, eds. TL Root and SH Schneider, Island Press.
Siegenthaler U, TF Stocker, E Monnin, D Lüthi, J Schwander, B Stauffer, D Raynaud, JM Barnola, H
Fischer, V Masson-Delmotte, J Jouzel (2006). Stable carbon cycle–climate relationship during the late
Pleistocene, Science 310:1313-1317.
Stenseth NC, A Mysterud (2002). Climate, changing phenology, and other life history traits: Nonlinearity
and match-mismatch to the environment, Proceedings of the National Academy of Sciences of the United
States of America 99(21): 13379-13381.
Visser ME, AJ Vannoordwijk, JM Tinbergen, CM Lessells (1998). Warmer spring events lead to mistimed
reproduction in Great Tits (Parus major), Proceedings of the Royal Society of London Series B: Biological
Sciences 265(1408): 1867-1870.
Walther GR, E Post, P Convey, A Menzel, C Parmesan, TJC Beebee, JM Fromentin, O Hoegh-Guldberg, F
Bairlein (2002). Ecological responses to recent climate change, Nature 416: 389-395.
11Puoi anche leggere
