Grape Technology vs. Climate Change: A Success Story or a Nightmare?

Abstract

Climate change impacts significantly on the biology of horticultural species, including grapevines. As shown in many studies, temperature changes influence the spread of grapevine cultivation, the timing and progression of vegetation phenophases, and the overall quality of grape production. Long-term studies on the dynamics of vegetation phenophases in relation to environmental conditions provide insights into the quantification of climate change effects. By observing changes in development and duration of key phenophases, researchers assess shifts in grapevine growth patterns and adaptability to evolving climatic conditions. While higher temperatures may initially seem beneficial, the complex interactions between climate factors cannot fail to impact grapevine health and wine quality. For example, extreme heat or changed rainfall patterns all pose challenges to grape cultivation. This Romanian vineyard-based research indicated notable increases in the average annual temperature. With some annual values of over 2.5°C beyond the multiannual average, these trends suggest a growing favorability for quality wine production in the region—but is that really so? The temperature changes recorded and their influence on grapevine phenology and wine characteristics highlight the need for ongoing research and proactive measures to ensure long-term sustainability and resilience of grape cultivation in the face of climate change.

1. Introduction

The unquestionable reality of climate change poses a challenge to traditions and practices in many areas of activity, the wine-growing world included. Given that wine is a particularly sensitive and supple agricultural product, there is a clear need for savvy producers to experiment with a range of adjustments that can withstand summer heatwaves, droughts, and milder winters, not to mention the ever more frequent harsh phenomena that are offshoots of climate change: forest fires, spring frosts, severe hailstorms, and flooding. There is compelling evidence that more disruptions are to be expected at an ever faster pace.

For close to three decades now, grape growers worldwide have been faced with significant changes in weather patterns, which, on the face of it, seems to have actually benefited regions never before associated with producing quality wines, such as England, that were quick to seize this unexpected opportunity of customizing local economies so as to join the wine world. By the same token, warmer growing seasons have facilitated the production of consistently exceptional wines in regions such as Champagne, Burgundy, Barolo, the Rhine, and Mosel valleys, where prime vintages used to be rare. Irrespective of such success, the character of these wines has unequivocally evolved, whether subtly or distinctly, due to the changing climate.

Studies carried out in the main vineyards in France have found an increase in the average temperature over the last 15 years of approximately 1°C, similar to both the minimum and maximum temperatures. These changes have already accelerated the course of the vegetative phenophases of the vine (differentiated according to the variety), causing an earlier ripening of the grapes of between 3 weeks and a month. Research done in Australia [1] indicated that grapes of different Vinifera cultivars zoned in Australian vineyards ripened, on average, 2 days earlier each year over the past 15 years. Also, other studies [2, 3, 4] highlight the gap in the development of the vegetative phenophases, including the ripening of the grapes that occur in the middle of the summer season, at the potential risk of altering the organoleptic characteristics of the grapes. Following studies carried out in Alsace, in Colmar, it was found that the period between destemming and harvesting moved forward and got shorter, while the ripening of the grapes took place under the conditions of increased temperature [5]. A study from INRA Bordeaux [6] believes that in view of the climate change trend, the zoning of varieties in wine plantations must take into account their thermal requirements in order to ensure the cycle of annual development: budding, flowering, veraison, ripening. In actual fact, the thermal conditions during the ripening period of the grapes are paramount for the grapes to reach the desired technological characteristics. Currently, the climate in the Bordeaux region is considered by the author to be intermediate, with an average air temperature (from April to October) of 16.5°C. The author believes that the average temperature increase of +2.4°C predicted for the end of the century remains within the limits of the thermal requirements of the main red varieties grown in the region. The edaphic factors, together with the climatic factors, influence the growth and fruiting phenophases of the vine, and implicitly the quality and quantity of the grape production.

Grapevine responds well in hilly regions in the Subcarpathian area of Romania and, to a lesser extent, in the plains. The altitude up to which the vine can be grown in Romania is 500–600 m, bearing in mind that with the increase in altitude, global radiation and the average air temperature decrease. The ideal conditions for vine cultivation are found at altitudes between 100 and 300 m.

In Romania, studies carried out by several authors [7, 8, 9] on the values of the limiting biotope factors for grapevine culture (as can be seen in Table 1) show that the level of climatic and eco-pedological factors is favorable for grapevine culture in well-defined cultivation areas in Romania, for both wine and table grape varieties. Climatic factors determine the area of ​​vine cultivation and guide production directions.

No.	Influencing factors		Measuring units	Restrictions
				Minimal	Maximal
1.	Length of vegetation period		days	160	>200
2	Thermal balance	global	°C	2900	>4000-5000
		active		2700	>3800-4000
		useful		1000	>1500-1800
3.	Absolute minimal temperature for unprotected vine cultivation		°C	Table grapes	-18 … -20
				Wine grapes	-20…-22
4.	Average temperature in warmest month		°C	18	>20–22
5.	Mean temperature at flowering		°C	15-17	30
6.	Mean temperature in soil		°C	5-6	25
7.	Real sunshine during vegetation		hours	1200-1300	>1800-2000
8.	Rainfall (annual average values)
	Low trellising system		mm	450	800-900
	Semi-high and high trellising system		mm	500-550	800-900
9.	Relative humidity		%	50	80-90
10.	Climatic factors interaction	Real heliothermal index	-	1,3	>2
		Hydrothermal coefficient	-	0,6	3
		Bioclimatic index of vine	-	5	15
11.	Critical ecoclimatic factors	Hail	-	Absent or sometimes
		Late and early hoar phenomena	-	Absent or at long intervals
		Glazed frost	-	Absent or at long intervals
		Excessive heat	-	Absent or at long intervals

Table 1.

Eco-climatic conditions for the economic culture of grapevine as per [7].

Temperature represents the most important climatic factor and is expressed by the sum total of the temperature values, average and extreme, reached during vegetation and during the period of relative rest. The minimum thermal balances (global Σt°g, active Σt°a, and useful Σt°u) for the economic culture of vine with extra-early and early ripening varieties are Σt°g = 2900°C, Σt°a = 2700°C and Σt°u = 1000°C. Medium ripening varieties require at least Σt^og = 3200°C, Σt^oa = 2900°C, Σt^ou = 1300°C, and those with late ripening: Σt^og = 3400°C, Σt^oa = 3200°C, Σt^ou = 1500°C. The average temperature of the hottest month (July) must be no less than 18°C for early varieties (table wine varieties), 20°C for average maturing varieties (quality wine varieties), and 22°C for late maturing ones (designation of origin wines). The minimum temperature during the flowering period (end of May, beginning of June, depending on variety and cultivation area) is 15°C for the opening of flowers and 17°C for pollen germination. The unprotected culture of the vine is possible only in areas where the absolute minimum temperatures in winter do not drop below −22°C in the case of wine varieties, or below −20°C for table grape varieties, provided that the frequency of such levels is a maximum of 1–2 years out of 10 [10].

Real insolation during the vegetation period must be at least 1200 hours for the culture of early varieties, 1400 hours for middle varieties, and 1500 hours for late varieties.

The annual precipitation must range from at least 450 mm for the low driving form to 500 mm for the semi-high forms, and 550 mm for the high driving forms, of which ⅔ needs to fall during the vegetation period. At precipitation values under 400 mm and 0.6 for the hydrothermal coefficient, grapevine culture is only possible under irrigation conditions. As a mesophytic plant, the humidity requirements for the grapevine vary during the vegetation period from one phenophase to another, subphases included. Thus, the phenophases of budding, and growing of shoots and berries are correlated with a higher value of the relative air humidity (70–80%), flowering with more than 55%, and the maturation of wood and berries with 50–60% humidity [10].

The areas designated for wine plantations must reach real heliothermic index (Ihr) values higher than 1.3, over 4 for the wine bioclimatic index (Ibcv), and over 3600°C for the oenoclimatic aptitude index (IAOe). Areas with recurrent climatic accidents need to be avoided: frosts in late spring and early autumn, hail, low temperatures during flowering, excessive heatwaves accompanied by drought during vegetation, or particularly cold currents during vegetative rest.

Research carried out worldwide on the impact of climate changes on the physiological and biochemical processes in the plant clearly points to repercussions for the development and duration of the main phenophases of the grapevine (budding, flowering, ripening, and grape ripening).

2. Case study: Romania, Vrancea County, Odobești vineyard

2.1 Multi-annual perspective

The climate of the area is temperate continental, with excessive nuances due to the presence of Eastern European air masses and Atlantic air masses from the west and northwest all year round, especially in the transition seasons, a climate similar to that of the Subcarpathian vineyards. The climatic elements in the southern part of Moldova generally tend not to show too great variations that would jeopardize the ecosystem for the culture of vines.

The Research and Development Station for Viticulture and Wine-making Odobești Meteorological Station located in the center of the vineyard, in the lower part of the Şarba plain (coordinates: 45°45”north latitude, 27°03″ east longitude, and 182 m altitude), indicates a multi-year (1946–2019) average value of the annual temperature of 10.7°C, with +22.1°C for July and − 1.6°C for January. The average annual thermal amplitude of approximately 23.7°C corroborates with that of absolute extremes of over 63°C (between −23.7°C and + 39.4°C) to highlight the prominent degree of thermal continentalism.

Global solar radiation has high values, around 130 kcal/cm² (multiannual average), ranging between 120 kcal/cm² on northern exposures and 160 kcal/cm² on southern exposures. An increase of 20% favors the early initiation of some phenophases (budding, flowering), while a decrease of about 20–30% leads to a significant drop in the amounts of accumulated sugars, compounded by an increase in total acidity [11].

The real insolation in the Odobești vineyard has values between 1869.3 hours/year (1984) and 2578.6 hours/year (2012), of which 1509.9 hours during the vegetation period (multiannual value of the period 1970–2019), with maximum values of 1782.6 and 1745.9 in 2012 and 2018, respectively.

The global thermal balance for vineyards in Romania records values between 2700 and 3600°C, the active one between 2600 and 3500°C, and the useful one between 1000 and 1700°C [10]. In Odobești, the values (2974.2–3932.0°C) of the global heat balance from the vegetation period (1970–2019) indicate that the conditions for grape ripening are up to the VI and VII epochs. The active and useful thermal balance from the vegetation period of 2844.9–3749.3°C and 1188.8–1987.5°C, respectively, shows high annual variability, with a peak in 2012 (Table 2).

Year	Global thermal balance	Active thermal balance	Useful thermal balance	Year	global thermal balance	Active thermal balance	Useful thermal balance
1970	3211.2	3086.7	1416.7	1996	3105.4	3096.8	1456.8
1971	3147.3	2978.7	1293.7	1997	3107.5	2984.1	1374.1
1972	3300.7	3198.7	1488.7	1998	3394.5	3394.5	1546.5
1973	3223.3	3145.6	1405.6	1999	3432.9	3370.5	1620.5
1974	3116.9	2966.2	1346.2	2000	3467.2	3461.3	1711.3
1975	3457.7	3374.7	1644.7	2001	3379.2	3407.4	1677.4
1976	2981.2	2928.4	1208.4	2002	3505.2	3424.2	1714.2
1977	3107.8	2942.1	1342.1	2003	3462.1	3373.9	1683.9
1978	2974.2	2848.8	1188.8	2004	3574.0	3142.1	1401.1
1979	3209.3	3081.3	1431.3	2005	3603.0	3165.5	1465.5
1980	2975.6	2844.9	1204.9	2006	3700.0	3191.5	1481.5
1981	3096.2	2995.6	1335.6	2007	3652.6	3579.4	1839.4
1982	3231.5	3066.1	1456.1	2008	3879.0	3473.2	1683.2
1983	3330.2	3259.7	1519.7	2009	3932.0	3502.2	1742.2
1984	3056.7	2892.8	1272.8	2010	3739.0	3432.4	1662.4
1985	3316.4	3251.0	1491.0	2011	3749.0	3314.3	1644.3
1986	3415.2	3281.4	1491.4	2012	3800.0	3737.5	1987.5
1987	3272.4	3110.0	1490.0	2013	3602.2	3523.1	1793.1
1988	3263.3	3151.5	1491.5	2014	3592.9	3508.1	1786.1
1989	3269.6	3246.5	1446.5	2015	3768.3	3688.9	1969.6
1990	3276.6	3210.8	1500.8	2016	3705.9	3688.0	1878.0
1991	3118.2	2970.6	1320.6	2017	3574.7	3478.9	1808.9
1992	3278.8	3125.7	1495.7	2018	3768.7	3749.3	1939.3
1993	3168.3	2902.9	1392.9	2019	3522.7	3377.8	1717.8
1994	3624.9	3582.8	1802.8	Multiannual mean	3395.5	3254.8	1552.3
1995	3331.8	3233.2	1553.2

Table 2.

Thermal balance values (global, active, and useful) from the vegetation period in Odobești vineyard (1970–2019).

The average temperature of 20.9°C calculated for the first and second decades of June, that is, the period when the flowering phenophase occurs, proves favorable to the biological processes that condition the pollination and binding of the berries (Table 3).

Year	Mean temp. of first 2 decades in June, °C	Mean temp. of warmest month (July), °C	Mean temp. of Aug., °C	Mean temp. of Sept., °C	Bioactive period (days)
1990	20.2	22.0	21.8	16.2	210
1991	19.2	21.9	20.2	16.5	192
1992	18.6	21.9	24.6	15.8	180
1993	20.1	20.7	20.9	16.2	174
1994	19.3	23.7	23.1	20.8	200
1995	21.1	24.0	21.6	15.7	187
1996	21.4	21.3	20.1	13.7	190
1997	20.3	21.2	19.8	14.3	200
1998	21.0	22.9	21.4	15.7	173
1999	22.2	23.6	21.2	18.0	183
2000	21.4	24.8	22.8	15.3	195
2001	19.6	24.3	24.2	16.9	192
2002	19.5	24.5	21.5	18.0	207
2003	22.3	22.1	23.1	15.9	199
2004	18.9	21.5	20.8	16.3	185
2005	17.9	21.5	21.2	17.6	187
2006	17.6	22.3	21.3	18.1	184
2007	23.1	25.4	23.4	17.4	205
2008	20.0	22.0	24.1	16.9	206
2009	22.0	23.7	22.9	18.9	217
2010	21.9	23.3	24.7	16.7	210
2011	21.5	22.6	22.1	20.0	216
2012	22.6	26.4	24.3	19.4	195
2013	21.1	23.1	23.5	16.4	214
2014	20.9	23.7	24.1	19.7	220
2015	22.9	25.0	24.5	20.2	205
2016	20.9	24.6	23.3	19.6	219
2017	21.3	22.6	23.9	18.9	220
2018	23.7	22.1	23.9	18.2	213
2019	23.1	22.1	23.9	19.0	218
Mean	20.9	23.0	22.9	17.4	199.8

Table 3.

Eco-climatic factors in Odobești vineyard between 1990 and 2019 as per [12, 13].

The multiannual value of the average temperatures in July, August, and September (23.0°C, 22.9°C, and 17.4°C, to be precise) indicates a thermal climate favorable to the growth of the berries, veraison, and full maturity.

In recent years (2010–2019), one can observe an upward trend that helps obtain harvests with higher concentrations of sugars, flavors, and phenolic substances [10]. The duration of the bioactive period from 1990 to 2019 was, on average, 199.8 days.

As regards grapevine culture, the frequency of harmful absolute minimum temperatures under −20°C, which causes the soil to freeze up to 60–70 is of particular importance for unprotected vines. The analysis of the absolute minimum temperatures recorded in the winter months over a period of 50 years found the lowest temperature in the air to be −22.7°C on January 14, 1985, the very day when the absolute minimum on the ground was also recorded at −28.6°C. The average of the lowest absolute minimum temperatures in the air during the analyzed period was −15.2°C and at the ground surface - 19.1°C. These values ​​confirm that the Odobești vineyard is located in a semi-protected vine cultivation area [12].

In the temperate continental climate, the vine requires an annual precipitation regime between 500 and 700 mm, of which at least 250–300 mm must be evenly distributed during the vegetation period as useful rainfall of over 10 mm [10]. In Odobești vineyard, the multiannual precipitation mean is 643.8 mm, of which 416.0 mm in the growing season, with a minimum of 164.9 mm in 1986 and a maximum of 693.4 mm in the year 2016 (Table 4).

Year	Rainfall, L/m^2		Year type	Year	Rainfall, L/m^2		Year type
	total	Veg. period			total	Veg. period
1990	498.0	289.0	A little dry	2005	900.8	620.5	Excessively rainy
1991	804.0	634.8	Excessively rainy	2006	663.1	497.9	Very rainy
1992	637.9	395.9	Normal	2007	916.5	431.8	Excessively rainy
1993	610.4	331.7	Normal	2008	490.3	329.3	A little dry
1994	362.5	205.9	Excessively dry	2009	465.2	187.0	Excessively dry
1995	531.1	379.5	Normal	2010	775.0	500.2	Very rainy
1996	835.5	592.5	Excessively rainy	2011	509.4	409.2	normal
1997	782.1	512.0	Very rainy	2012	447.2	298.8	A little dry
1998	695.2	374.1	Normal	2013	813.4	555.4	Excessively rainy
1999	649.8	468.9	Rainy	2014	903.3	494.0	Very rainy
2000	451.1	287.9	Very dry	2015	650.6	330.0	Normal
2001	523.7	453.4	Rainy	2016	1049.0	693.4	Excessively rainy
2002	662.2	369.4	Normal	2017	655.2	407.6	Rainy
2003	409.7	264.3	Very dry	2018	561.8	405.8	Normal
2004	522.0	381.8	Normal	2019	546.8	370.8	Normal

Table 4.

Rainfall regime and the characteristics of the 1990–2019 period in the Odobești vineyard.

Although there has not been a decrease in the amount of precipitation in recent years (2008–2019), with an annual average of 655.6 mm and 415.1 mm during the growing season, there appears to be an uneven distribution along the year, as well as an alternation between dry and rainy years.

The precipitation deficit appears especially in the winter period and the beginning of the vegetation period (April–May, with a direct impact on the initiation of the phenophases in the vines, as well as in July–August). The driest years were 1994 with 205.9 mm during the growing season and 2009, with only 187.0 mm, compared to the multiannual average (416.0 mm). Abundant precipitation was recorded in 2016, in the period preceding flowering (values almost triple compared to normal), which placed the harvest under manna attack, both on the leaves and on the bunches.

The analysis of precipitation over a period of 30 years (1990–2019) allows for a synthetic characterization of each year (Table 4). The data for the Odobești vineyard shows that there are excessively rainy and very rainy years (1–2 years) as well as excessively dry and very dry years (1–2 years) interspersed with normal years [12].

2.1.1 Synthetic ecoclimatic indices

To assess the heliothermal and water resources of a vineyard or wine-growing center, a series of synthetic ecological indicators are used that integrate the combined action of two or three climatic factors [9]: real heliothermal index—IHr; hydrothermal coefficient—CH [14]; bioclimatic index of the vine—Ibcv [15]; oenoclimatic aptitude index—IAOe [16]; De Martonne aridity index—IarDM [17]; Huglin index—IH [18]; night coolness index—IF [19].

In the Odobești vineyard, the average value of the real heliothermal index (IHr) from 1970 to 2019 is 2.4, with a minimum of 1.7 in 1976, 1978, 1980, and 1984, and a maximum of 3.5 in 2012, indicating an adequate temperature and light for the ripening of table and wine grape varieties (Table 5).

Year	IHr	CH	Ibcv	IAOe	Iar DM	IH	IF
1970	2.0	1.5	5.1	4296	36	1874	11.1
1971	1.9	1.8	4.5	4150	37	1801	10.5
1972	2.0	2.0	3.6	4123	49	1954	11.0
1973	2.1	0.8	10.1	4617	23	1905	11.8
1974	1.9	1.7	4.6	4123	33	1798	12.2
1975	2.2	1.0	7.5	4653	25	2139	13.7
1976	1.7	1.6	4.7	4093	39	1687	11.3
1977	2.0	1.3	6.4	4306	24	1650	11.1
1978	1.7	2.1	3.7	3947	42	1653	10.2
1979	2.1	1.7	4.9	4305	39	1877	12.4
1980	1.7	1.4	5.5	4067	38	1802	11.0
1981	2.0	1.5	5.4	4265	37	1768	12.2
1982	2.1	1.2	6.5	4398	27	1817	13.9
1983	2.2	1.2	6.7	4569	21	2051	12.7
1984	1.7	1.6	4.6	4013	38	1745	13.0
1985	2.3	1.0	8.4	4695	24	2038	11.2
1986	2.5	0.5	18.1	5033	17	2172	12.2
1987	2.1	1.3	5.8	4332	34	1985	12.9
1988	2.0	0.9	8.3	4464	31	1930	12.4
1989	2.0	1.4	5.4	4407	25	1949	12.6
1990	2.4	0.9	9.8	4781	23	2012	11.0
1991	1.8	2.1	3.4	3909	40	1748	12.0
1992	2.2	1.3	6.4	4454	31	1988	10.6
1993	2.1	1.1	7.0	4293	30	1864	11.2
1994	2.8	0.6	14.6	5168	16	2331	15.3
1995	2.4	1.2	7.2	4648	26	2090	11.4
1996	2.3	1.9	4.4	4311	41	1899	10.8
1997	2.1	1.7	4.8	4242	39	1767	9.8
1998	2.2	1.1	7	4674	33	2100	11.5
1999	2.6	1.4	6.2	4729	30	2089	14.0
2000	2.9	0.8	11.1	5117	21	2143	11.1
2001	2.6	1.3	6.4	4761	24	2118	12.8
2002	2.6	1.1	7.5	4791	30	2173	13.2
2003	2.7	0.8	11.0	4947	20	2158	11.5
2004	2.1	1.2	6.6	4487	25	1917	11.9
2005	2.0	1.9	3.8	4163	44	1882	13.4
2006	2.2	1.6	5.2	4423	32	1961	13.2
2007	3.2	1.2	7.8	5119	41	2346	12.2
2008	2.5	0.9	8.5	4872	22	2187	11.9
2009	2.8	0.5	16.4	5166	21	2329	13.5
2010	2.3	1.5	5.2	4570	37	2190	12.1
2011	2.7	1.2	7.2	4789	24	2194	13.8
2012	3.5	0.8	12.2	5471	21	2597	12.7
2013	3.0	1.6	5.8	4877	37	2305	11.0
2014	2.8	1.4	6.1	4832	41	2329	13.8
2015	3.4	0.9	10.4	5318	28	2477	15.1
2016	3.2	1.9	4.9	4930	46	2451	14.0
2017	3.1	1.2	8.1	5048	29	2329	13.1
2018	3.4	1.1	8.8	5339	26	2551	13.1
2019	2.7	1.1	7.8	4824	24	2331	13.1
Average	2.4	1.3	7.2	4598	31	2051	12.3

Table 5.

Eco-climatics synthetic indices in the Odobești vineyard (1970–2019) as per [12, 13].

The CH has a multiannual average value of 1.3, with a minimum of 0.5 (1986 and 2009), which indicates extremely dry years, and a maximum of 2.1 (1978 and 1991), showing very rich years in precipitation.

The Ibcv with an average value of 7.2 is considered optimal for vine culture. In recent years (2000–2019) Ibcv recorded the most favorable values in 2000 (10.1), 2003 (11.0), 2009 (16.4), and 2012 (12.2), while the lowest value was recorded in 2005 (3.8).

IAOe with a multiannual average value of 4598 places Odobești vineyard in the area for white and red wines for current consumption, as well as quality wines with designation of origin. In certain years, this index places the vineyard among areas with a high degree of favorability for the production of quality white and red wines with designation of origin as well as table grape varieties.

The IarDM for said vineyard registered values between 16 (in 1994) and 49 (in 1972), and a multiannual average of 31, which indicates a semi-humid forest-steppe climate.

The IH, with a multi-year average of 2047, places the vineyard in the temperate climate class—IH3 (IH-1)*. However, in the last 10 years, the values went up to 2400 (2011–2020 average), thus placing the Odobeşti wine-growing area in the warm temperate climate class—IH4 (IH +1)*. The IF shows a multi-year value of 12.3, which qualifies as a wine-growing climate class with cold nights—IF₃ (IF +1) area*.

Overall, the values of the synthetic ecological indicators in the Odobești vineyard describe an area that is well-balanced and propitious for the cultivation of vines, with very good favorability for the cultivation of quality white wine varieties and good favorability for quality red wine varieties.

2.2 Recent climatic analysis 2020–2022

Maximum daily temperatures showed positive values yearly, with a steady increase from the winter to the summer season. The highest values of the maximum daily temperatures were recorded in the months of June and July. Daily minimum temperatures had negative values in December–February, with the lowest in January and the highest in July.

Average monthly temperatures showed an upward evolution in the first part of the year, with a maximum of 24.3°C in July (2021) and in August (2020 and 2022), followed by a downward trend, with a minimum in January.

Over the 2020–2022 period, the average air temperature was 12.3°C, 1.6°C higher than normal (10.7°C), and the average monthly temperatures were above the multiannual averages except for the month of April. A significant increase in average monthly temperatures was also observed in the winter period (December–February).

For the same time span, the maximum absolute temperature in the air reached 37.1°C (July 2021), and the absolute minimum (January 2021) showed −15.0°C in the air and − 17.8°C at the ground surface.

Based on the analysis of values for global heat balance (Σ °t global), active (Σ °t active), and useful (Σ °t useful) during the vegetation period, the following aspects emerge for the Odobești wine-growing area for 2020–2022:

• the global thermal balance, with values of 3344.0, 33586.9, and 3608.4°C over the 3 years of the study was favorable for the ripening of grapes;

• the active thermal balance with values of 3186.7, 3505.6, and 3543.5°C ensured the biological threshold for the growth and development of the vine;

• the useful thermal balance, ranging between 1566.7 and 1793.4°C, was beneficial for the ripening of grapes for both wine and table varieties.

The sums of global, active, and useful temperature degrees for the years in question exceeded the multiannual averages (Tables 6 and 7).

Month	Global temperature °C				Active temperature °C
	Multi- annual	2020	2021	2022	Multi- annual	2020	2021	2022
IV	346.2	367.1	262.6	347.4	254.6	302.2	105.3	266.1
V	529.4	489.6	510.5	549.6	513.2	489.6	510.5	549.6
VI	619.4	653.3	609.0	680.6	612.9	653.3	609.0	680.6
VII	695.8	729.1	753.5	742.5	689.3	729.1	753.5	742.5
VIII	682.3	751.8	708.6	752.2	674.9	751.8	708.6	752.2
IX	522.4	617.5	499.8	514.6	509.9	617.5	499.8	514.6
Σ	3395.5	3608.4	3344.0	3586.9	3254.8	3543.5	3186.7	3505.6

Table 6.

Sum of temperatures °C for vegetation period over 2020–2022 period.

Month	Useful temperature °C
	Multi- annual	2020	2021	2022
IV	71.0	82.1	15.3	76.1
V	218.4	179.6	200.5	239.6
VI	313.2	353.3	309.0	380.6
VII	375.6	419.1	443.5	432.5
VIII	361.7	441.8	398.6	442.2
IX	212.4	317.5	199.8	214.6
Σ	1552.3	1793.4	1566.7	1785.6

Table 7.

Sum of temperatures °C for vegetation period over 2020–2022 period (continuation).

Precipitation, along with temperature, is a very important climate factor for grapevine culture. The influence of humidity is of interest when one takes into account the ratio of precipitation level and air hygroscopicity.

According to several authors [7, 8, 18, 20], vine culture is possible in temperate zone areas where the annual precipitation is between 400 and 700 mm, of which 250–300 mm is during the vegetation period.

Measurements in the Odobeşti vineyard show a multiannual average of annual precipitation of 643.8 mm, of which 416.0 mm during the vine vegetation period.

Over the 2020–2022 period, the amount of precipitation was both wanting and very unevenly distributed. The rainfall regime of 2020 was extremely deficient, with only 421.6 mm, of which 215.0 mm is in the vegetation period (Table 8), which makes it one of the driest years in the area under study.

Month	Rainfall (mm)				Hygroscopicity %
	Multi-annual	2020	2021	2022	Multi-annual	2020	2021	2022
I	29.7	0.4	47.0	6.4	80.3	66.9	83.5	62.7
II	30.0	9.8	4.4	4.8	77.8	63.1	75.6	57.4
III	36.1	20.2	46.8	1.2	70.2	56.9	65.3	48.4
IV	50.8	5.2	41.0	65.8	65.8	39.0	65.3	58.1
V	80.3	55.6	22.8	31.6	65.9	60.1	63.8	54.5
VI	86.8	81.6	134.6	48.2	65.7	64.1	70.2	54.0
VII	83.0	28.2	40.0	51.0	65.5	57.0	63.2	53.5
VIII	64.4	13.0	45.0	31.6	64.9	50.1	64.3	59.4
IX	50.7	31.4	6.2	26.8	68.7	56.4	62.0	65.7
X	53.0	65.4	9.6	1.2	74.9	78.1	62.8	60.3
XI	42.3	12.2	12.0	50.8	79.3	82.0	75.2	83.4
XII	36.7	98.6	76.2	23.8	81.8	92.2	81.6	88.5
Annual	643.8	421.6	485.6	343.2	71.7	63.8	69.4	62.2
Veg. period	416.0	215.0	289.6	255.0	66.1	54.5	64.8	57.5

Table 8.

The rainfall regime and air hygroscopicity during the 2020–2022 period.

Save June, when the amount of precipitation (81.6 mm) was close to normal (86.8 mm), most months saw amounts well below the normal values, prolonged drought settling in, and the precipitation deficit rising from 1 month to the next.

The amount of precipitation for 2021 was higher than in 2020 and 2022, but still below normal values, while the distribution along the vegetative rest period was disproportionate, with a deficit in February (−25.6 mm) and a slight surplus in January and March.

During the vegetation period, the amount of precipitation (289.6 mm) registered a deficit of 126.4 mm compared to the multi-year value for the Odobești vineyard (416.0 mm). The distribution of precipitation was uneven, with a significant deficit in May (−57.5 mm), moderate in July (−43.0 mm), and September (−41.1 mm), but also a substantial surplus in June (+47.8 mm). Specifically, the amount of precipitation recorded in 2021 was 485.6 mm below normal for the period (643.8 mm), which contributed to further extending the deficit from the previous year (2020). In turn, 2022 was extremely dry in the Odobești vineyard, with 343.2 mm of annual precipitation. The period of vegetative rest (January–March) lacked precipitation (−83.4 mm), while for the vegetation period (April–September) the deficit reached −161.0 mm compared to normal (416.0 mm), and was particularly significant in May (−48.7 mm). All this, on top of the already existing deficit (2021 and 2020 in particular), led to a sharp decrease in the water reserve in the soil.

Regarding the relative humidity of the air, it is known that vines normally carry out their growth and fruiting processes at values between 50 and 80%, those lower than 40% hinder photosynthesis, and below 20% block this activity.

During the analyzed period, the relative humidity of the air had values specific to the regions with a continental climate, which indicates the close correlation between this climatic element and the air temperature. Thus, in the years 2020 and 2022, the relative humidity of the air was 63.8% and 62.2%, respectively, being below the multiannual average.

2.2.1 Climatic indicators with a synthetic character

The combined action of the climatic factors is rendered via synthetic indicators (Table 9), which integrates the action of several ecoclimatic factors so as to facilitate the characterization of the climatic potential of a vineyard or wine-growing center, and also specify the requirements for the grape varieties studied.

Climatic elements	Mean 1970-2019	2020	2021	2022	Mean 2020-2022
Global thermal balance, (Σt°g)	3395.5	3608.4	3344.0	3587.1	3513.2
Active thermal balance, Σt°a)	3254.8	3543.5	3186.7	3505.8	3412.0
Useful thermal balance, (Σt°u)	1552.3	1793.4	1566.7	1785.8	1715.3
Mean temp in first 2 decades of June	20.8	21.1	18.3	21.9	20.4
Mean temp in July, °C	22.2	23.5	24.3	24.0	23.9
Mean temp in August, °C	21.5	24.3	22.9	24.3	23.8
Mean temp in September, °C	17.1	20.6	16.7	17.2	18.2
Mean annual temp. t °C	10.7	13.0	11.3	12.7	12.3
Mean annual temp vegetation period, °C	18.2	19.7	18.3	19.6	19.2
Minimal temp in the air, °C	-22.7	-9.8	-15.0	-10.5	-11.8
Maximum temp in the air, °C	39.4	37.0	37.1	36.7	36.9
No of days with temp > 30 °C	28.9	67	46	55	56.0
∑ annual sunshine, (hours)	2194.9	2516.0	2309.5	2461.3	2428.9
Σ sunshine vegetation period, (hours)	1509.9	1725.0	1597.5	1679.5	1667.3
Σ annual rainfall, mm	643.8	421.6	485.6	343.2	416.8
Σ rainfall vegetation period, mm	416.0	215.0	289.6	255.0	253.2
Bioactive period, no. days	199.8	219	183	208	203.3
Real heliothermal index (Ihr)	2.4	3.1	2.5	2.9	2.8
Hydrothermal coefficient (CH)	1.3	0.6	0.9	0.7	0.7
Viticultural bioclimatic index (Ibcv)	7.2	15.5	9.6	12.4	12.5
Oenoclimatic suitability index (IAOe)	4598	5304	4745	5109	5053
Huglin heliothermal index (IH)	2047	2448	2123	2382	2318
Martone aridity index (Iar-DM)	31	18	23	15	18.7
Cooling nights index (IF)	12.3	14.6	11.0	11.4	12.3

Table 9.

Summary of the main climate components in the analyzed period compared with multiannual average.

The overall analysis of the main climatic factors in the Odobești vineyard over the period 2020–2022 compared to the multiannual averages highlights the following:

• an increase in the average annual temperature from 10.7°C (multiannual value) to 13.0°C (2020), and implicitly of the thermal balance values;

• an increase in average temperatures for July, August, and September;

• a reduction in annual and vegetation period precipitation amounts accompanied by very uneven distribution;

• twice the number of days with temperatures exceeding 30°C (56 days) compared to the multiannual value (28.9 days).

Systematic recording and processing of climate data for the period 2020–2022 provided the prerequisites for calculating binary and ternary climate indicators as well as multi-criteria climate indicators that describe the wine-growing climate of a wine-growing plot, wine-growing center, vineyard, or wine-growing region [21].

IHr values were between 2.5 and 3.1, exceeding the multiannual value and the numbers found in the literature (1.75–2.25), which shows an increase in heliothermal resources and optimal ripening conditions for late varieties in the southern part of Moldova. CH index was between 0.6 and 0.9, around the lower limit described in the literature (0.7–1.8), a testimony to insufficient humidity combined with increased temperatures. The Ibcv values for the same period were very high at 15.5 in 2020 and 12.4 in 2022, a fact that points to very high heliothermic resources and very low water resources and 9.6 in 2021, respectively. IAOE scored between 4745 (2021) and 5304 (2020), which is indicative of an area both opportune for quality white wines and boasting high favorability for red wines.

The DeMartonne aridity index saw values between 15 (2022) and 23 (2021), with an average of 18.7, which describes a semi-arid climate in the Odobești vineyard over the period in question.

The Huglin heliothermal index provides information related to the thermal potential in the culture of table and wine grape varieties with different grape ripening periods. For the Odobești vineyard, the sum total of the Huglin index values was 2448 in 2020, 2123 in 2021, and 2382 in 2022. As per these values, a warm climate class—IH5 was confirmed for the year 2020, with limits varying between 2400 and less than/equal to 3000, respectively, while a climate class IH4 specific to areas with warm temperate climate values above 2100 and less than/equal to 2400 was found to be the case for 2021 and 2022.

IF index is relevant for the ripening period of the grapes. It was obtained by summing the minimum temperatures of the respective month. The IF index was calculated for the month of September at 14.6 in 2020, 11.0 in 2021, and 11.4 in 2022. Such values fall within the IF² class range (> 14 ≤ 18), corresponding to the climate class with temperate nights in 2020 when the ripening of medium varieties grapes is ensured. The IF⁴ class range (< 12), corresponding to very cold nights in 2021 and 2022, when September is not favorable for grape ripening and production quality depends on solar radiation and insolation.

2.3 Grape cultivation in Odobești vineyard

The Research and Development Station for Viticulture and Oenology Odobeşti has been managing data on climate evolution since the 1940s and offers a perspective on how climate change affects local grape varieties and implicitly the quantity and quality of local wines. It also manages valuable databases on the phenology of the varieties, the ripening dates of the grapes of the different varieties in the area, the quality of the grapes and wines, etc. Based on these data, recommendations are made for choosing the right varieties to plant here and for applying optimal culture technologies.

The biological material that provides the corpus for this study is represented by five Romanian varieties of vines for white wines, some created at the Research and Development Station for Viticulture and Winemaking Odobeşti: Şarba, Băbeasca gri, Mioriţa and Vrancea, and Fetească regală, all Vitis vinifera.

2.3.1 ŞARBA grape variety

This was obtained by free fertilization of the Riesling Italian variety (Proles occidentalis). Authors: Popescu Gheorghe, Oşlobeanu Milu, Poenaru Ion, Bădiţescu Margareta. It was approved in 1972 [22]. The vegetation period is between 165 and 177 days. The budding season is late (end of April); the grape veraison begins at the beginning of August, and the full maturity of the grapes is achieved about 3–4 weeks after the Chasselas dore variety, in the second decade of September. The average production is 20 t/ha. At full maturity, the grapes accumulate a berry sugar content of 187 g/L, reaching up to 215 g/L in favorable years, and an acidity of 4.8–5.2 g/L sulfuric acid.

2.3.2 BĂBEASCĂ GRI grape variety

A variation of the Băbească neagră variety (Proles orientalis). Authors: Popescu Gheorghe, Oşlobeanu Milu, Poenaru Ion, Bădiţescu Margareta. It was approved in 1975 [22] Băbeasca gri variety has a vegetation period ranging between 190 and 205 days. Budding happens in the first half of April, the grape veraison takes place in the first half of August. It is a late-ripening variety, with grapes reaching full maturity at the beginning of October. It ensures high and constant productions that vary between 15 and 20 t/ha, and a good capacity to accumulate sugars. At full maturity, the grapes accumulate a content of sugars in the berries between 165 and 185 g/L, reaching almost 200 g/L in favorable years, and an acidity that varies between 6.0 and 6.7 g/L sulfuric acid.

2.3.3 MIORIŢA grape variety

This is a natural hybrid of the Coarnă albă variety (Proles orientalis). Authors: Gheorghe Popescu, Margareta Bădiţescu, Nicolae Varga, Zaharia Victoria. It was approved in 1980 [22]. The Mioriţa variety has a vegetation period between 167 and 182 days. Budding happens in the third decade of April, veraison is in the second decade of August, and full maturity of the grapes takes place in the last decade of September–early October. At full maturity, this late-ripening variety accumulates a sugar content of 165 g/L, reaching up to 180 g/L in favorable years, with high acidity values between 5.6 and 7.5 g/L sulfuric acid.

2.3.4 VRANCEA grape variety

Obtained by crossing the hybrid combination (Traminer x Armaş) with Fetească regală variety. Authors: Mihu Ghică, Bosoi Ionica, Pușcalău Marioara. It was approved in 2018 and patented in 2019. The vegetation period is between 164 and 175 days. Budding takes place in the second decade of April, blooming in the first decade of June, veraison in the first half of August, and full ripening in the second decade of September. The sugar accumulation potential in the must is 192–223 g/L, while total acidity is 5.48 g/L tartaric acid [23].

2.3.5 FETEASCĂ REGALĂ grape variety

This Romanian local grape variety is the result of natural hybridization between Fetească albă x Grasă de Cotnari [22] and, at the moment, is planted on the largest surface in Romania. Budding starts in the early days of April, veraison occurs in the first part of August, and full ripening is reached 3–4 weeks after the Chasselas doré variety. The grape production varies from one cultivated area to another, from 11 t/ha in Blaj to 27 t/ha in Odobeşti, with an average of 15–20 t/ha. It accumulates sugars from 170 to 180 g/L to 200–210 g/L, with a total acidity that must vary between 4.5 and 7.0 g/L sulfuric acid while the capacity for overripening is much reduced, with sugar accumulations not in excess of 220–235 g/L.

2.4 Climatic influences on grape phenophases and technological composition

Authors [24, 25, 26, 27] were keen to study the behavior of grape varieties in their areas of origin under certain ecological conditions. The climatic changes in the last few years evidenced an average country-wide warming of 0.3°C, more pronounced in the eastern part, and a lower rainfall regime with uneven distribution all along the year.

The climatic conditions of 2020–2022 made possible in-depth research on the behavior of grape varieties created at S.C.D.V.V. Odobești (Şarba, Băbeasca gri, Miorița, and Vrancea), plus Fetească regală, the cumulative effect of stressful environmental factors included, as well as on their agrobiological and technological properties.

Research on the sequence and physiological completion of the phenophases in relation to the ecological factors of 2020–2022 highlights the fact that the vegetation phenophases were conditioned in many ways by the level and cumulative action of climatic factors and the hereditary specificity of each variety (Table 10).

Phenophases	Grape variety	2020		2021		2022
		date	Useful; ∑ °t	date	Useful; ∑ °t	date	Useful; ∑ °t
Budding	Şarba	13.IV.	60.3	1.V	27.3	15.IV	54.5
	Băbească gri	12.IV.	56.4	28.IV	12.2	15.IV	54.5
	Mioriţa	14.IV.	60.3	4.V	50.3	16.IV	59.3
	Vrancea	13.IV.	60.3	2.V	38.3	16.IV	59.3
	Fetească regală	10.IV.	52.1	30.IV	17.7	15.IV	54.5
Flowering	Şarba	03.VI.	248.1	11.VI	282.6	31.V	273.8
	Băbească gri	04.VI.	259.9	14.VI	318.0	1.VI	284.0
	Mioriţa	05.VI.	268.5	14.VI	279.9	2.VI	291.6
	Vrancea	04.VI.	256.0	11.VI	271.6	29.V	253.1
	Fetească regală	03.VI.	256.3	10.VI	281.7	29.V	257.9
Veraison	Şarba	4.VIII	871.8	12.VIII	836.6	1.VIII	823.3
	Băbească gri	9.VIII	940.8	17.VIII	886.4	6.VIII	880.0
	Mioriţa	11.VIII	964.2	19.VIII	906.8	9.VIII	914.9
	Vrancea	3.VIII	850.5	10.VIII	809.9	27.VII	776.2
	Fetească regală	3.VIII	850.2	8.VIII	789.0	29.VII	803.2
Full maturity	Şarba	14.IX	528.3	17.IX	368.3	2.IX	454.0
	Băbească gri	17.IX	528.2	23.IX	320.9	11.IX	467.3
	Mioriţa	16.IX	568.5	25.IX	310.4	9.IX	389.1
	Vrancea	10.IX	483.9	15.IX	374.0	28.VIII	446.2
	Fetească regală)	9.IX	515.4	13.IX	383.2	26.VIII	404.6
Leaf fall	Şarba	16.XI	267.8	26. X	98.8	9.XI	252.3
	Băbească gri	16.XI	227.6	26. X	66.4	9.XI	181.6
	Mioriţa	16.XI	239.9	26. X	64.6	9.XI	203.0
	Vrancea	16.XI	321.7	26. X	120.3	9.XI	323.1
	Fetească regală	16.XI	334.6	26. X	141.2	9.XI	354.1
Length of vegetation period (days)	Şarba	216		178		207
	Băbească gri	217		182		208
	Mioriţa	215		179		208
	Vrancea	216		176		207
	Fetească regală	219		180		208

Table 10.

The vegetation phenophases of studied varieties.

In 2020, full ripening of the grapes occurred in the first and second decade of September, at average temperatures of 22.3°C, which led to the acceleration of physiological processes and faster ripening, too. In 2021, this phenophase occurred later, starting with the second decade of September for mid-ripening varieties (Şarba and Vrancea) and the third decade of September for late-ripening varieties (Băbeasca gri and Miorița), at average temperatures considerably lower than in the previous year (16.4°C).

In 2022, full ripening of the grapes was unusually early, viz. end of August—first decade of September, under the influence of high average temperatures of 22.6°C. During the 3 years of study, the first grapes to reach full maturity were Vrancea, the earliest on August 28 2022, and the latest on September 13 2021, to be followed by the Şarba variety 3–4 days later.

Miorița and Băbeasca gri varieties reached full maturity on September 9–112,022 (the earliest) and on September 23–252,021(the latest), ca 8–14 days after Fetească regală.

The duration of the grape ripening process was shorter, 32.0–39.5 days on average, with small differences among the varieties, which further confirms the influence of recent climatic changes in the Odobești wine-growing area (Tables 11 and 12).

	Șarba				Băbească gri				Miorița
	2020	2021	2022	Mean	2020	2021	2022	Mean	2020	2021	2022	Mean
Harvest date	16.09	20.09	10.09	-	7.09	23.09	14.09	-	17.09	24.09	15.09	-
Sugars, g/L	213	251	233	232	213	212	230	218	188	169	194	183
Total acidity g/L tartaric acid	5.5	7.8	5.2	6.2	7.	8.1	7.1	7.5	6.2	7.8	6.	6.7
pH	3.68	3.57	3.64	3.63	3.3	3.23	3.51	3.37	3.4	3.25	3.5	3.42
Gluco-acidimetric index	59	49	68	59	45	40	50	45	46	33	49	43
Total dry substance %	23.8	22.1	22.7	22.9	21.4	20.3	21.1	20.9	20.7	19.1	20.2	20
Total polyphenols g/L gallic acid	0.25	0.22	0.24	0.24	0.36	0.32	0.35	0.34	0.24	0.21	0.23	0.23
Total polyphenolic index (IPT)	2.8	2.4	2.7	2.6	4.0	3.4	3.8	3.7	3.5	2.7	2.6	2.9

Table 11.

Technological characteristics of studied varieties.

	Vrancea				Fetească regală
	2020	2021	2022	Mean	2020	2021	2022	Mean
Harvest date	15.09	20.09	9.09	-	15.09	20.09	9.09	-
Sugars, g/L	205	203	221	210	192	183	197	191
Total acidity g/L tartaric acid	5.1	6.2	5.1	5.5	6.3	6.8	6.1	6.4
pH	3.62	3.52	3.6	3.61	3.5	3.4	3.5	3.53
Gluco-acidimetric index	61	50	66	59	47	41	49	46
Total dry substance %	23.1	21.3	22.6	22.3	22.1	20.6	21.5	21.4
Total polyphenols g/L gallic acid	0.32	0.27	0.30	0.30	0.29	0.23	0.27	0.,26
Total polyphenolic index (IPT)	3.9	3.5	3.6	3.7	3.5	2.8	3.0	3.1

Table 12.

Technological characteristics of studied varieties (continuation).

As concerns harvest time, that is, the 1st decade of September in 2022 and the 2nd decade of September in 2020 and 2021 for the Vrancea and Şarba varieties, the 2nd decade of September in 2020 and 2022, and the 3rd decade of September in 2021 for late-ripening varieties (Băbeasca gri and Miorița), the analysis highlighted a real potential for the accumulation of sugars in the must.

The sugar content of grapes is influenced by biological and ecological factors as well, as biological singularities of the variety, cultivation technology, insolation, temperature, humidity, soil characteristics, etc. As a result, the chemical composition of the must reveals different accumulations both from one variety to another and from 1 year to another. As seen in Tables 11 and 12, all grape varieties boast sugar concentration values higher than those quoted in the literature [28].

The acidity of the must in the four varieties stayed within normal limits in 2021 and scored much lower in 2020 and 2022 as a result of the lack of precipitation and the very high temperatures during harvest and ripening. Of the four varieties, the Băbeasca gri variety got the highest total acidity content, with an average value of 7.53 g/L tartaric acid, followed by Miorița, with an average of 6.73 g/L tartaric acid.

The balance between sugars and acidity of the must is also evidenced by the value of the gluco-acidimetric index. This index scored very high in 2020 and 2022 when the very low acidity of the must be varied between 46 for Băbeasca gri and 68 for Şarba. In 2021, deemed as climatically normal, the gluco-acidimetric index saw lower values, i.e., between 33 for Miorița and 50 for Vrancea, which is a guarantee for quality wines. The pH of the must had similar average values for the Băbeasca gri and Miorița varieties (3.37–3.42), scoring slightly lower in 2021 for Şarba (3.73), while Vrancea had values close to the control variety (3.53).

The total dry substance content (%) of the most was higher for Şarba, between 22.16–23.82%, averaging 22.92%, followed by Vrancea, with an average value of 22.39%, both above the Fetească regală variety (21.47%). The lowest values were recorded for Băbeasca gri (20.98%) and Miorița (20.03%). One should note that in the severe drought conditions of 2020 and 2022, the total dry matter content was higher, which signals a degree of berry dehydration, also highlighted by the lower moisture content (76.18–79.75%).

The total polyphenols, shown in grams/L of gallic acid, were higher for Băbească gri (0.32–0.36 g/L gallic acid) than the control variety, while Miorița totaled lower values (0.21–0.24 g/L gallic acid). The total polyphenolic indices (IPT) had the same distribution by varieties and harvest years, i.e., higher values for Băbeasca gri (3.4–4.0) and Vrancea (3.5–3.9), and lower values for the Miorița (2.6–3.5) and Şarba (2.4–2.8) varieties, which have green-yellowish skin and pulp.

3. Conclusions

The results compellingly show that early development stages already set in motion a general advancement of grapevine phenology and a curtailing of the growth period. Such an impact, corroborated by the further increase in the frequency and intensity of extreme climate events during sensitive phenological phases, is likely to have adverse effects on both the final yield and its quality and the suitability for grapevine cultivation of each region. Phenology advancement is expected to perturb the ripening period, as grape maturity occurs earlier during the hottest part of the vegetative cycle, customarily the warmest part of summer. The above is boosted by extremely high-temperature regimes insofar as they interfere with biochemical and physiological processes, more specifically berry sugar-acid and flavonoid levels, as well as color and aroma.

A trend shift between different white varieties as concerns the date of harvest was demonstrated and the data was pooled with sugar content increases and acidity reductions. We posit therefore that increased probability for unbalanced wines due to higher sugar and lower acid concentrations in the grape can be correlated with the predictable escalation of the number of early harvests (plausible for white varieties) and the corresponding reduction in the number of late harvests.

In conclusion, in Odobești vineyard an increase in average annual temperatures was recorded by 0.6–2.3°C, an uneven distribution of water resources, recording dry years, such as 2003 (−234 mm), 2009 (−178 mm), 2020 (−222 mm), and 2022 (−301 mm) against an average of 643 mm and rainy years such as 2005, 2007, 2014 but especially 2016 with an excess of over 400 mm.

The full ripeness of the grapes evolved according to the variety and was affected by the increase in temperatures and the increased frequency of days with maximum temperatures above 30°C recorded in July, August, and even in September.

All things considered, the wine industry is aware of the urgent need to make adjustments that take heed of climate change so as to preserve unique, centuries-old traditions and practices. By championing innovative approaches and sustainable practices, wine producers hope to continue creating exceptional wines while keeping the environment safe for generations to come.

Overall, the wine industry is recognizing the urgent need to adapt to climate change to preserve the unique traditions and practices that have been in place for centuries. By embracing innovative approaches and sustainable practices, wine producers hope to continue delivering exceptional wines while also safeguarding the environment for future generations.