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.

1.1 Introduction to CropWatch agroclimatic indicators (CWAIs)

This chapter describes environmental and crop growth conditions over the period from October 2023 to January 2024, ONDJ, 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 2024 ONDJ 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 2009 to 2023. Although departures from the 2009-2023 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., 2019-2023). 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.

1.2 Global overview

Temperatures keep raising at an alarming rate. According to the Copernicus Climate Change Service (C3S) of the European Union, as well as reports from the National and Oceanic Atmospheric Administration (NOAA) of the United States of America, 2023 was a record setting year when it comes to global warming: Earth’s global surface air temperatures was 1.48°C warmer than the 1850-1900 pre-industrial level. It was 0.17°C warmer than the previous record, which was set in 2016. Several other records were broken as well: Close to 50% of the days were warmer than the 1850-1900 level, and two days in November were, for the first time, more than 2°C warmer.

2023 not only saw record breaking temperatures, but also a prolonged drought in the Amazon. The World Weather Attribution project has concluded that human-caused global warming played a significantly larger role than El Niño in intensifying the 2023 Amazon drought. Water levels in the Amazon river were never as low in 120 years of record keeping. Scientists warn that the Amazon basin may soon reach a tipping point, and the rainforest will turn into grassland. This would not only be devastating for the indigenous communities, but for crop production in the wider Amazon area as well.

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 October 2023 to January 2024 total from 2009-2023 average (15YA), in percent.

In South America, the patterns of rainfall departures from the 15YA were similar to those reported in the previous bulletin: A decline in precipitation by more than 30% for the Amazon basin, the Cerrado and North-East of Brazil. Chile, Southern Brazil, most of Argentina and the coast line of Peru had average to above average rainfall. In Central America, conditions were average. They improved to average and slightly above average (+10 to +30%) in the Mexican highlands and the southern High Plains in the USA. The northern Plains, as well as most of Canada, had a rainfall deficit ranging from -10 to -30%. The only crop production region of Canada with average rainfall was Ontario. In Europe, rainfall was mostly above average. The only exceptions were the north-east of Spain (<-30%) and northern Italy (>-30% to <-10%) and Greece. In the European part of Russia as well as Russia's region east of the Ural, northwest and northeast China, southern India, Indonesia, the Darling Downs in Australia, the countries on the southern border of the Sahel and East Africa, precipitation was by more than 30% above average. The Sahel, Maghreb (Mediterranean North African coast), Pakistan, southern Africa and southwest Australia had a large rainfall deficit, exceeding more than -30%. In China, conditions were mixed: South-East China and the Tibetan Plateau had a deficit ranging from -10 to -30%. In the other regions, precipitation was average to above average. While these maps depict the 4 month average of this monitoring period, the rainfall deficit in southern Africa is worse than depicted by the map. Rainfalls virtually ceased in mid-January, at the peak of the rainy season.

1.4 Temperatures

Figure 1.2 Global map of temperature anomaly (as indicated by the TEMP indicator) by CropWatch Mapping and Reporting Unit: departure of October 2023 to January 2024 average from 2009-2023 average (15YA), in °C.

In North-and South America, temperatures were mostly above average (+0.5 to +1.5°C). In the Amazon basin, the Cerrados, Mexico and the Southern Plains in the USA, they were above average by more than +1.5°C. The regions with average temperatures were Argentina, Uruguay, Paraguay, Parana and the Pacific coastline from Chile to Peru. In Europe, the Scandinavian countries and northern Russia were the only regions in which average temperatures were cooler by more than 0.5°C. Russia west of the Ural had average temperatures. Above average (+0.5 to +1.5°C) and higher were recorded for most of Europe, the Maghreb, South- and East Africa, South and East Asia, as well as Oceania. Temperatures departed by more than +1.5°C in West and Central Asia, as well as the Sahara. Equatorial Africa experienced average temperatures.

1.5 RADPAR

Figure 1.3 Global map of photosynthetically active radiation anomaly (as indicated by the RADPAR indicator) by CropWatch Mapping and Reporting Unit: departure of October 2023 to January 2024 average from 2009-2023 average (15YA), in percent.

Photosynthetically active solar radiation was rather variable within continents. In South America, Parana and all of the crop production regions of Argentina, solar radiation was more than 3% below the 15YA. It was also below the average along the coast of Peru. To the contrary, it was more than 3% above average for the Cerrados and the northeast of Brazil. Central America experienced slightly above average solar radiation (+1 to +3%). In the Mexican Highlands, as well the Western Corn Belt in the USA, the radiation deficit exceeded -3%. The South-East and Northern Plains were slightly more sunny (+1 to +3%). For the rest of the USA, as well as for most of Canada, a deficit ranging between -1 to -3% was recorded. The Maghreb, Western and Central Europe had positive departures, ranging from +1% to more than +3%. Russia an both sides of the Ural had a strong deficit, exceeding -3%. A strong deficit was also recorded for Africa along the equator and East Africa. Southern Africa, where the rainy season usually starts in November, had a strong positive departure by more than +3%. In Western, Central and South Asia, solar radiation was average or slightly above (+1 to +3%). Eastern and Southern China, most of Japan, as well as South-East Asia, the Malay Archipelago and south-western Australia had a strong positive departure by more than +3%.

1.6 BIOMSS

Figure 1.4 Global map of biomass accumulation (as indicated by the BIOMSS indicator) by CropWatch Mapping and Reporting Unit: departure of October 2023 to January 2024 average from 2009-2023 average (15YA), in percent.

Biomass is estimated as a function of rainfall, temperature and solar radiation, which comprehensively reflects the impact of agroclimatic conditions on crop growth. Thanks to the above average rainfall, positive departures from the 15YA by more than +5% were estimated for Central Chile, Argentina and Parana in Brazil. The strong rainfall deficit in parts of Brazil resulted in decline of estimated biomass by more than -5%. Conditions were average in Central America the South-East of the USA and the Canadian Prairies. They were more favorable for the Central Highlands in Mexico, the Southern Plains and the Midwest of the USA. California and Western Canada had a slight positive departure. For all of Africa north of the Sahel, as well as well as the crop production regions of West Africa and most of its South, a strong negative biomass production by more than 5% below average was estimated. In southern Europe, biomass production was estimated as ranging from -5 to -2% below average. Some pockets, along the Mediterranean coastline from Catalonia in Spain to the North of Italy, had even stronger negative departures by more than -5%. The rest of Europe, as well as the Caucasus and Kurdistan, had positive departures by more than +5%. In Central Asia, including the Hindukush, negative departures dominated. In South Asia, as well as in Eastern Asia strong positive departures by more than +5% were observed. For Southeast Asia, estimates were average. Conditions in Australia ranged from negative departures by more than -5% in the South-West to more than +5% in along the East Coast and the Darling Downs.