6.1 How do the climate and environment directly affect the conditions required for food production?

This section considers the environmental conditions or factors required for food production, their link to the climate and the environment, and how they will therefore be affected by climatic and environmental change and degradation.

6.1.1 Land and soils

Requirements for food production:

Land: physical space, accessibilitySoils: sufficient soil organic matter, depth, drainage, aeration and appropriate pH.

Impacts of climatic and environmental change:

The availability of suitable agricultural land is almost synonymous with the availability of suitable soils. In addition to the impacts of soil degradation (see Chapter 5), as the climate changes, and as precipitation patterns alter, the suitability of soils for growing crops is likely to change. For example, drought can lead to dry exposed soils, and may lead to desertification, while extreme flooding can lead to waterlogging, causing anaerobic inhospitable soils.

6.1.2 Sunlight

Requirements for food production:

Sufficient daylight hours and sufficient light intensity to support crop growth

Impacts of climatic and environmental change:

While daylight hours are outside of climatic and environmental control, the intensity of light reaching crop plants depends on air clarity and weather. Smog and particulate carbon from car and factory emissions is so thick in certain parts of the world (e.g. Bangladesh) that the reduction in sunlight reaching crops was sufficient to hinder their growth.

6.1.3 Water

Requirements for food production:

Green water (i.e. precipitation) and blue water (i.e. ground sources of water or aquifers). Sufficient volume for irrigation needs, and appropriate technology and infrastructure for irrigation.

 

Impacts of climatic and environmental change:

Water availability (of both green and blue water) depends on volume and frequency of rainfall, as well as on soil drainage, infrastructure and competing demands from non agricultural activities. Projected changes in precipitation, soil moisture, run-off and evaporation across the globe indicate that, at a very rough approximation, places that are currently wet are set to get wetter, while places that are currently dry are set to get drier (both on a climatic scale and in terms of extreme weather events such as droughts and flooding). Both drought and flooding are likely to have negative impacts on crop production, although there are likely to be some regions in which changes in precipitation may bring benefits for food production.

6.1.4 Insects

Requirements for food production:

Insects and other invertebrates for pollination, pest control and maintenance of the soil environment (e.g. aeration of the soil, or aiding with the breakdown of organic matter).

Impacts of climatic and environmental change:

Insect pollinators and other invertebrates providing a range of ecosystem services are known to be under threat from climate change and other environmental influences. Temperature, changing seasonal patterns, and increased or decreased rainfall can all have serious consequences for the animals which provide vital ecosystem services for agriculture. For example: Changing temperatures can affect the emergence times of insect larvae or adult forms, in some cases leading to a loss of synchronicity with the plants they pollinate (whether wild or cultivated), leading to crashes in the insect population, a phenomenon called phenological advancement. The ranges which the insects inhabit may shift as average temperatures rise, leading to changes in the insect communities of particular regions. It is thought that this may have a positive effect on some insect species at mid- to high-latitudes, as warming temperatures decrease their mortality and allow for northward range expansion. Extreme weather events, such as flooding, which are likely to increase in frequency, can also have adverse effects on invertebrates: for example, following severe flooding in the UK in 2007, it was predicted that soil compaction and a decrease in the earthworm population would lead to poorer yields in the following years.