Chapter 1. Global agroclimatic patterns

Chapter 1 describes the CropWatch Agroclimatic Indicators (CWAIs) rainfall (RAIN), temperature (TEMP), and radiation (RADPAR), along with the agronomic indicator for potential biomass (BIOMSS) in 105 global Monitoring and Reporting Units (MRU). RAIN, TEMP, RADPAR and BIOMSS are compared to their average value for the same period over the last fifteen years (called the “average”). Indicator values for all MRUs are included in Annex A table A.1. For more information about the MRUs and indicators, please see Annex B and online CropWatch resources at www.cropwatch.com.cn. Compared to the previous bulletin, some of the larger MRU with several different phenology and agroclimatic conditions have been subdivided. Thus, the number of MRU was increased by 40 in this bullletin.

1.1 Introduction to CropWatch agroclimatic indicators (CWAIs)

This bulletin describes environmental and crop growth conditions over the period from July 2023  to October 2023, JASO, referred to as "reporting period". CWAIs are averages of climatic variables over agricultural areas only inside each MRU and serve the purpose of identifying global climatic patterns. For instance, in the "Sahara to Afghan desert" MRU, only the Nile Valley and other cropped areas are considered. MRUs are listed in Annex B. Refer to Annex A for definitions and to table A.1 for 2023 JASO numeric values of CWAIs by MRU. Although they are expressed in the same units as the corresponding climatological variables, CWAIs are spatial averages limited to agricultural land and weighted by the agricultural production potential inside each area.

We also stress that the reference period, referred to as "average" in this bulletin covers the 15-year period from 2008 to 2022. Although departures from the 2008-2022 are not anomalies (which, strictly, refer to a "normal period" of 30 years), we nevertheless use that terminology. The specific reason why CropWatch refers to the most recent 15 years is our focus on agriculture, as already mentioned in the previous paragraph. 15 years is deemed an acceptable compromise between climatological significance and agricultural significance: agriculture responds much faster to persistent climate variability than 30 years, which is a full generation. For "biological" (agronomic) indicators used in subsequent chapters we adopt an even shorter reference period of 5 years (i.e., 2018-2022). This makes provision for the fast response of markets to changes in supply.

Correlations between variables (RAIN, TEMP, RADPAR and BIOMSS) at MRU scale derive directly from climatology. For instance, the positive correlation between rainfall and temperature results from high rainfall in equatorial, i.e., in warm areas.

Considering the size of the areas covered in this section, even small departures may have dramatic effects on vegetation and agriculture due to the within-zone spatial variability of weather. It is important to note that we have adopted an improved calculation procedure of the biomass production potential in the bulletin based on previous evaluation.

1.2 Global overview

October, the last month of this monitoring period, was the fifth consecutive month of record-warm global temperatures. According to the National and Oceanic Atmospheric Administration (NOAA), there is a greater than 99% probability that 2023 will rank as the warmest year on record. From January to October, the largest positive temperature departures were observed all the way from the South of the USA to Patagonia in South America, the Maghreb, Eastern Europe, a belt along the equator in Africa and Eastern China. Near average temperatures were observed only in the Western USA. Apart from some regions in Antarctica, no place on Earth observed cooler than average temperatures.

The onset of El Niño changed some global rainfall patterns. Argentina and Eastern Africa, which experienced strong rainfall deficits until mid 2023, started to receive higher precipitation, causing flooding in Ethiopia, Kenya and Somalia. The people in these countries are going through crisis upon crisis.

1.3 Rainfall

Figure 1.1 Global map of rainfall anomaly (as indicated by the RAIN indicator) by CropWatch Mapping and Reporting Unit: Departure of July 2023 to October 2023 total from 2008-2022 average (15YA), in percent.

In South America, the pattern of the rainfall deficit changed from the previous report. Paraguay, Uruguay, southern Argentina and Chile received average to above average rainfall, while a rainfall deficit had been recorded before. The Andes in Bolivia, Peru, and Ecuador, as well as the Amazon basin, Central and Northeastern Brazil, had a strong rainfall deficit of more than -30%. Conditions in Central America were average. The Mexican Highlands, as well as the western USA and the Southern High Plains, had a strong rainfall deficit (<-30%). The only exception was the West Coast, where rainfall was average. In the northern High Plains of USA, as well as the Canadian Prairies, the deficit ranged from -10 to -30%.  Most of the Midwest and the East of the USA received normal precipitation. The strongest deficit was observed for East Africa, and the countries North of the Sahel. Only south-east Africa had average to above precipitation. In the Levant, the drought conditions continued, with a rainfall deficit greater than -30%. In the Caucasus and Central Asia, apart from Afghanistan, the situation had improved to above average (+10 to +30%) and more. The Ural region in Russia, as well as Kazakhstan, South Asia, South-East Asia and Eastern China had average to above average precipitation. In Australia, a strong rainfall deficit, greater than -30%, was observed for all crop production regions, apart from the southwest of Australia, where the deficit ranged from -10 to 30%.

1.4 Temperatures

Figure 1.3 Global map of temperature anomaly (as indicated by the TEMP indicator) by CropWatch Mapping and Reporting , Unit: departure of July 2023 to October 2023 average from 2008-2022 average (15YA), in °C.

Except for the Cape Province in South Africa, all land surfaces experienced average or above temperatures ranging from 0.5 to 1.5ºC above the 15YA. The strongest positive departures of +1.5ºC or more were recorded for the Amazon Basin and the Mexican Highlands. Much warmer temperatures (>+1.5ºC) were recorded for Central Europe, the Levant, Eastern Siberia, and the North China Plain. In Southern Africa, as well as the South of Argentina, Chile and the West Coast of the USA, South Asia and northern Siberia, temperatures were close to the long-term average.

1.5 RADPAR

Figure 1.4 Global map of photosynthetically active radiation anomaly (as indicated by the RADPAR indicator) by CropWatch Mapping and Reporting Unit: departure of July 2023 to October 2023 average from 2008-2022 average (15YA), in percent.

In South America, only the northeast of Brazil had above average solar radiation by more than +3%. The same regions in South America that received above-average precipitation had below-average solar radiation by more than -3%. In the other areas of South America, the radiation was average, as well as in Central America and the southern United States. The Mexican Highlands and the Southeast of the USA had above average solar radiation (+1 to +3%), whereas in the West and the Southern Plains of the USA, solar radiation was average. The West Coast, as well as the Midwest and Northeast of the USA, Quebec, Ontario, and the Canadian Prairies, had below-average radiation by more than -3%. In all of the other regions of North America, solar radiation was reduced by -1 to -3%. A reduction in solar radiation by -1 to -3% was also observed for the southeast of Africa. In the African countries along the equator, solar radiation was above average. Western Europe had average solar radiation, whereas in Eastern Europe, it was above average. In the Middle East and Central Asia, it was below average by -1 to -3%. In South and Southeast Asia and the North China Plain, solar radiation was above average by more than +3%. In Southeast China, it was below average by -1 to -3%. Positive departures were recorded for the Malay Archipelago and all of Australia.

1.6 BIOMSS

Figure 1.5 Global map of biomass accumulation (as indicated by the BIOMSS indicator) by CropWatch Mapping and Reporting Unit: departure of July 2023 to October 2023 average from 2008-2022 average (15YA), in percent.

Estimated biomass production was by more than 5% below average in almost all of the Americas. This was mainly due to a rainfall deficit. The regions with positive departures were Patagonia, all of Chile, and the West coast of the USA. The Midwest and north-eastern regions of the USA had average biomass production. In Africa, the biomass anomaly map also matched the rainfall departure map. Only the southeast of Africa had positive departures in biomass estimates. Scandinavia and most of Western Europe, apart from the Iberian Peninsula, had a positive departure of biomass by more than +5%. For the European regions of Russia, a negative departure by -2 to -5% had been estimated. In Central Asia, the Ural, the Indo-Gangetic Plain, East and Southeast Asia, a positive departure had been estimated as well. For the Malayan Archipelago, a negative departure by -2 to -5% had been calculated, whereas for Australia, the negative departure was even stronger (<-5%).