Desiccation cracks in a mud puddle. Photo Jakob Owens.

Drought is caused by either cold or hot conditions. Many people living outside the extreme climate zones are unaware of the fact that the largest deserts on Earth are the Antarctic and the Arctic, the latter of which includes Greenland, northern Canada, northern Alaska, Spitsbergen, and parts of Iceland and northernmost Siberia. Life conditions are very hostile in these areas and the species diversity of plants and animals is extremely low due to the low temperatures and the lack of water. It takes very special adaptations to live on ice. In addition, severe storms generate a chill factor that can kill people in minutes.

The other large deserts are sand and rock deserts situated in warm climate areas, except for the Gobi and the Kalahari deserts. It is not the heat that make them deserts, it is the scarcity of rain. Without water, no life. The third largest desert is Africa's Sahara, about 3/4 of the size of Antarctica. The Arabian desert, in size only 1/5 of Antarctica, is number four.

A desert is defined as an area with less than 250 mm precipitation per year. With that definition, about 1/3 of all land is classified as desert. It is remarkable how thoughtlessly people in the high-income countries of the world use water. Water wars are to be expected when the medium-income countries follow suite. Lack of water presents a greater problem than global warming. My database includes 2074 pages about drought and heat in different geographical areas, seen in the table.

DROUGHT-HEAT subregister (pages) 1033
Africa 156
Sahara Desert 2
Africa 15
Algeria 7
Angola 2
Burundi 1
Chad 4
Egypt 18
Eritrea 1
Ethiopia 26
Gambia 1
Ghana 1
Kenya 10
Libya 3
Mali 2
Mauretania 1
Mozambique 1
Morocco 11
Namibia 1
Niger 2
Nigeria 2
Rwanda 1
Sahel & North Africa 9
Senegal 1
Somalia 2
South Africa 4
Sudan 13
Tanzania 4
Tunisia 6
Uganda 4
Zimbabwe 3
America Central - West Indies 10
America North 122
America South 40
Antarctic 3
Arctic - Greenland 37
Asia 604
of which >5
China 178
Indonesia 94
India 69
Thailand 41
Asia 35
Sri Lanka 25
Vietnam 24
Burma 21
Israel 19
Japan 16
Cambodia 16
Near-Middle East 16
Iran 10
Syria 10
Uzbekistan 10
Kazakhstan 9
Philippines 7
Laos 6
Atlantic Islands 3
Australia 13
Europe 1037
of which >5
Sweden 393
Europe 181
Germany 88
Finland 83
Spain 48
England 40
Denmark 40
Italy 36
France 31
Norway 31
Iceland 25
Russia 17
Turkey 14
Switzerland 12
Netherlands 11
Poland 7
Austria 6
Ukraine 6
Indian Ocean 2
Mediterranean 6
Pacific Ocean 1
World 37