Ground Environment X Asia And South America
Lorean Hoefert
NOAA and NASA satellites monitor drought across all of the continents of the world, with the agricultural areas of many continents severely impacted by drought in 2022. The global precipitation, evapotranspiration, soil moisture, groundwater, and vegetative health tools created from this satellite data are presented in the Global Drought Information System's (GDIS) Global Drought Monitor housed at NCEI. The year began drier than normal across parts of southern Europe, with the Iberian Peninsula in the midst of a prolonged dry spell that had lasted at that point for much of 2021. Drier-than-normal conditions developed across most of Europe during March 2022 and recurred across parts of Europe throughout the summer and fall. Temperatures were above normal across most to all of the continent in January and February, but excessive heat dominated the continent from May to August, resulting in extreme evapotranspiration that exacerbated the dry conditions. Above-normal temperatures returned in October and November.
Drought shifted east during September, lowering soil moisture and groundwater levels in southeastern China where high evapotranspiration rates damaged crops; these conditions persisted through the fall. In Africa, the Sahel region and much of East Africa were dry for the last three to four years. The persistent dryness and high temperatures/evapotranspiration in 2022 depleted soil moisture, lowered groundwater, and desiccated vegetation. With 2022, East Africa experienced four consecutive failed rainy seasons, a climatic event not seen in at least 40 years that created what the United Nations deemed a humanitarian emergency as more than 23 million people in Ethiopia, Somalia, and Kenya were faced with severe hunger/famine. In South America, drought stretched from Peru and central and southern Brazil to the agricultural lands of Argentina, with 2022 marking the second year of dry conditions in many of these areas. Satellite-based data revealed low groundwater, dry soils, and poor vegetative health. Rain fell across some of the drought areas during some months of 2022, but it was not enough to erase deficits that built up over 12 to 24 months. Temperatures were frequently above normal, enhancing evapotranspiration that added to the stress on crops in Argentina and Uruguay.
Dry conditions persisted across much of Canada, South America, Australia, northern China, and the Mediterranean region during October 2023, while beneficial precipitation fell across some of the drought areas in the other continents. Anomalously warm conditions continued to dominate all of the continents. It was a record-warm October for Asia and South America, with Africa, Europe, and North America having the second warmest October. For many continents, record heat extended back several months, increasing evapotranspiration which exacerbated drought in the dry areas and, in some cases, countering beneficial precipitation. A significant portion of the world's agricultural lands was still suffering from low soil moisture and groundwater levels, and satellite observations showed stressed vegetation on all continents. Drought has reduced crop yields and raised prices of foodstuffs worldwide. The GEOGLAM Crop Monitor indicated that agriculture was most threatened in parts of the Americas, East Africa, eastern Europe, southern Asia, and parts of Australia and Indonesia. The Famine Early Warning System Network (FEWSNet) revealed significant food insecurity continuing in parts of Central and South America, Southwest Asia, and much of Africa. The Reuters news agency noted that, with the release of their State of Global Water Resources 2022 report in October, the World Meteorological Organization said that the hydrological cycle was increasingly out of balance due to climate change and made a call for a fundamental policy shift towards better monitoring. Reuters added that the United Nation's research arm, the UN University's Institute for Environment and Human Security, warned in their Interconnected Disaster Risks report that the world is heading towards a series of environmental "tipping points" that could cause irreversible damage to water supplies and other life-sustaining systems.
Southeast Europe and Mediterranean coastal areas were drier than normal during October 2023, while most of Europe to the west and north was wetter than normal. This precipitation anomaly pattern persisted for the last 2 to 3 months. Temperatures were warmer than normal across the southern half of the continent and cooler than normal in Scandinavia, making October 2023 the second warmest October, continent-wide, in the 1910-2023 NOAA/NCEI record. Warm anomalies have been persistent throughout the summer, giving Europe the warmest multi-month periods from June-October through September-October, and, combined with anomalous warmth earlier in the year, the warmest February-October and January-October. Dry conditions spread northward from the south and east at longer time scales, with much of Europe from the Mediterranean to the Baltic Sea dry at 2- to 5-year time scales, according to the Standardized Precipitation Index (SPI). The excessive heat has increased evapotranspiration, making drought conditions worse. Soils were dry from the Mediterranean and Caspian Sea to northern Europe, with the satellite-based (GRACE) indicator of groundwater revealing low groundwater across most of Europe. Satellite observations of vegetative health (Vegetative Health Index, VHI) revealed stressed vegetation over most of the continent. The European Combined Drought Indicator showed the most severe drought in eastern and Mediterranean parts of Europe, with 48.6% of the EU-27 territory in Drought Watch, Warning, or Alert conditions, which is more than last month.
October was wetter than normal across large swaths of Asia, with drier-than-normal areas occurring over parts of India, northern China to eastern Siberia, and parts of Southwest Asia. At longer time scales, the SPI revealed dryness in parts of Russia and India at 2- to 6-month time scales; parts of Southeast Asia and northern China to western and southern Russia at 1- to 4-year time scales; and Southwest Asia from the last 6 months to 6 years with the intensity of drought and area covered increasing at the longer time scales. October 2023 temperatures were warmer than normal across virtually the entire continent, with Asia having the warmest October, continent-wide, in the NOAA/NCEI record. Persistent widespread warmth over the last several months gave Asia the warmest multi-month periods on record for March-October through September-October. The excessive warmth increased evapotranspiration across much of Asia, especially in Russia and northern China, according to the Evaporative Stress Index (ESI). The lack of precipitation and high evaporation dried soils in southern parts of Asia, as well as parts of Russia and China, as seen on satellite-based products (GRACE), and groundwater levels were significantly lowered (GRACE). Satellite observations (VHI) revealed poor vegetative health across much of Russia and especially severe from Southwest Asia to northern China and Mongolia. Drought conditions were confirmed over northern, eastern, and coastal southwestern parts of India on the India Drought Monitor, covering about 26.3% of the nation, which is more than last month. Some short- or long-term drought was indicated on some of the islands in the Southwest Pacific on the NIWA Island Climate Update maps, mostly in the south, north, and east at 1 to 3 months and central to eastern islands at 6- to 12-month time scales.
October continued dry across much of the Mediterranean coast (the Maghreb region) of Africa, as well as central and southern parts of the continent. Eastern Africa (Horn of Africa) was wetter than normal in October, which was a beneficial break from months to years of deficient rainfall in the region. The dry areas expanded in size at longer time scales to 6 months, according to the SPI. Much of North Africa was very dry at 12- to 60-month time scales, with dryness expanding in the south and appearing in East Africa beginning at 12 months. Most of Africa was warmer than normal this month, with October 2023 ranking as the second warmest October, continent-wide. Excessive warmth earlier in the year resulted in the warmest multi-month periods from the last 2 months (September-October) back to the beginning of the year (January-October). The excessive warmth increased evapotranspiration, as seen on the ESI. Satellite (GRACE) observations revealed persistent low soil moisture and groundwater in the Maghreb and adjacent northern regions, over parts of the Horn of Africa, and parts of central to southern Africa, with the worst conditions in the north and central regions. Satellite observations of vegetative health (VHI) revealed stressed vegetation over the Maghreb region and much of southern Africa. An analysis by the African Flood and Drought Monitor estimated 21% of the continent in drought at the end of October, which is about the same as last month.
Like last month, most of Australia was drier than normal during October 2023. Monthly temperatures were much warmer than normal in western Australia, slightly warmer than normal in the east, and near to cooler than normal in central regions. According to the Australian Bureau of Meteorology, the continent had the fifth driest October in the 1900-present record and driest August-October. The SPI shows dry conditions continent-wide at 2- to 3-month time scales, with wet conditions in north-central areas at 6 to 12 months and still very dry to the west and east. Wet conditions dominate at longer time scales, except along the southwest and northeast coasts. The ESI indicated enhanced evapotranspiration over western and eastern areas due to warmth during October and previous months. Dry soils stretched from the west coast to east coast, with wet soils in the north and southeast, according to GRACE soil moisture data. The GRACE data showed low groundwater in the west and east. These anomaly patterns were confirmed by Australian Bureau of Meteorology and Australian Combined Drought Indicator analyses, which also showed low streamflows along the west, east, and southern coasts and some areas on these coasts with low water storage levels.
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