Agriculture
Many livestock and crops are affected by high temperatures. Millions of birds have been lost to heat waves. Milk production and reproduction in cattle are also reduced. Crop yields are sometimes also reduced during heat waves.
Droughts may come about, which kills off many livestock and crops that have no more water
Countries that depend on agriculture very much may be in financial trouble
Farmers who depend on their crops or livestock for a living will make less money, making it very hard for them
With less crops and livestock produced, prices will go up so it may be more difficult for people to afford things
Transportation
Aircrafts lose their lift at high temperatures, and airports may have to close during times of extreme heat, causing them to lose a lot of money
Sometimes concrete roads, highways or train rails can gain too much heat and expand, which causes them to buckle and distort. After this happens, the repairs cost a lot of money
Water
During a heat wave, a lot more water will be used. Water is used to cool bridges and big metal structures susceptible to heat failure. With more fires breaking out during heat waves, a lot more water will have to be used by the fire department. People will also be using more water for their own individual needs. Water (from water sources like reservoirs, springs, e.t.c) will also dry up faster
As the demand for water increases, prices go up too. This can reduce people’s household disposable incomes
It can be more difficult to manage fires that break out because of the heat, with less water available so there may be more damage done
It is also pretty difficult to have a thriving economy when there is less water for industrial, farming and individual use