WINETECH Technical Yearbook 2020

Climate change in the viticulture sectors: Overview of long-term

This article summarises extensive statistical climatic analysis into normalised bar graphs, graphics that better highlight increases and decreases in weather over regions and months. Land and ocean surface temperatures, continue to increase above the average 132-year record held within the world meteorological organisation. The average surface temperature of the earth has risen by about 0.9°C since the late 19th century, a change driven largely by increased carbon dioxide into the atmosphere. The five warmest years on record taking place since 2010, 2016 being the hottest on record, followed by 2019, 2018, 2017 and 2014 respectively. Not only was 2016 the warmest year on record, but eight of the 12 months that make up the year (January to September, with the exception of June) the warmest on record for those respective months. January 2016 was the hottest January ever recorded, and recently in 2019 June, July and September was the hottest ever recorded for those months. This is globally and locally alarming. The period April 2018 to March 2019 was the warmest 12 month period on record for Europe. Australia recently had its warmest March on record. Africa is one of the continents most vulnerable to climate change, and regions at lower latitudes are especially vulnerable as they already suffer from intense heat. Climate change on a South African scale

based on the annual average temperatures from1901-2018 highlights the warming that is of concern (#knowyourstripes). Scientists continue to highlight the alarming warming trend that stands out from the noise of natural variation that sceptics tend to push on weather phenomenons like El Nino, but still we are warmer today than in the 1900s. In view of climate change, economic pres- sures and future limitation of water avail- ability to the agricultural sector, informed decisions regarding the suitability of envi- ronments for viticulture are paramount lo- cally and globally. Every local environment has unique diurnal temperature variations due to the inland penetration of the sea breeze and other local effects, such as wind, topography, coastline orientation, slope angle and aspect. Continuous monitoring of extreme environments is hampered by the sparse and/or irregular distribution of meteorological stations, the difficulties in accessing data from government data custodians, the quality of the data is not assured, and data is costly. Our under- standing of climate is meteorological vari- ables in a given region over a long period, usually over a 30-year interval, as opposed to weather which is a particular condition at a particular place over a short period of time within years or over years. This article uses two spatial networks of long-term climate data for the average period of 1980-2014, see figure 1.

climate trends in the Western Cape (PART 1)

APRIL 2020

TARA SOUTHEY: Centre for Geographical Analysis, Department of Geography and Environmental Studies, Stellenbosch University, Stellenbosch KEYWORDS: Climate, Western Cape, climate change

WARMING STRIPES FOR SOUTH AFRICA W FROM 1901 - 2018 WW

#showyourstripes

Annual average temperatures for South Africa from 1901-2018. Each stripe highlights the annual temperature difference compared to the long term mean (the first stripe is 1901 and the last stripe is 2018). (Source of graphic: Ed Hawkins. Data source: Berkeley Earth, NOAA, UK Met Office, MeteoSwiss, DWD.)

WINETECH TECHNICAL YEARBOOK 2020 18