GCAM v7.1 Documentation: Common Assumptions

Documentation for GCAM
The Global Change Analysis Model

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Common Assumptions

These assumptions are shared throughout the GCAM model.

Regional Resolution

Geopolitical Regions

GCAM subdivides the world into 32 geopolitical regions, representing countries or collections of countries (see Table below).

GCAM Region Countries
Africa_Eastern Burundi, Comoros, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Mauritius, Reunion, Rwanda, Sudan, Somalia, Uganda
Africa_Northern Algeria, Egypt, Western Sahara, Libya, Morocco, Tunisia
Africa_Southern Angola, Botswana, Lesotho, Mozambique, Malawi, Namibia, Swaziland, Tanzania, Zambia, Zimbabwe
Africa_Western Benin, Burkina Faso, Central African Republic, Cote d’Ivoire, Cameroon, Democratic Republic of the Congo, Congo, Cape Verde, Gabon, Ghana, Guinea, Gambia, Guinea-Bissau, Equatorial Guinea, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Sao Tome and Principe, Chad, Togo
Argentina Argentina
Australia_NZ Australia, New Zealand
Brazil Brazil
Canada Canada
Central America and the Caribbean Aruba, Anguilla, Netherlands Antilles, Antigua & Barbuda, Bahamas, Belize, Bermuda, Barbados, Costa Rica, Cuba, Cayman Islands, Dominica, Dominican Republic, Guadeloupe, Grenada, Guatemala, Honduras, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Montserrat, Martinique, Nicaragua, Panama, El Salvador, Trinidad and Tobago, Saint Vincent and the Grenadines
Central Asia Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Mongolia, Tajikistan, Turkmenistan, Uzbekistan
China China
Colombia Colombia
EU-12 Bulgaria, Cyprus, Czech Republic, Estonia, Hungary, Lithuania, Latvia, Malta, Poland, Romania, Slovakia, Slovenia
EU-15 Andorra, Austria, Belgium, Denmark, Finland, France, Germany, Greece, Greenland, Ireland, Italy, Luxembourg, Monaco, Netherlands, Portugal, Sweden, Spain, United Kingdom
Europe_Eastern Belarus, Moldova, Ukraine
European Free Trade Association Iceland, Norway, Switzerland
Europe_Non_EU Albania, Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, Turkey
India India
Indonesia Indonesia
Japan Japan
Mexico Mexico
Middle East United Arab Emirates, Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Palestine, Qatar, Saudi Arabia, Syria, Yemen
Pakistan Pakistan
Russia Russia
South Africa South Africa
South America_Northern French Guiana, Guyana, Suriname, Venezuela
South America_Southern Bolivia, Chile, Ecuador, Peru, Paraguay, Uruguay
South Asia Afghanistan, Bangladesh, Bhutan, Sri Lanka, Maldives, Nepal
Southeast Asia American Samoa, Brunei Darussalam, Cocos (Keeling) Islands, Cook Islands, Christmas Island, Fiji, Federated States of Micronesia, Guam, Cambodia, Kiribati, Lao Peoples Democratic Republic, Marshall Islands, Myanmar, Northern Mariana Islands, Malaysia, Mayotte, New Caledonia, Norfolk Island, Niue, Nauru, Pacific Islands Trust Territory, Pitcairn Islands, Philippines, Palau, Papua New Guinea, Democratic Peoples Republic of Korea, French Polynesia, Singapore, Solomon Islands, Seychelles, Thailand, Tokelau, Timor Leste, Tonga, Tuvalu, Viet Nam, Vanuatu, Samoa
South Korea South Korea
Taiwan Taiwan
USA United States

Table: Mapping from GCAM region to country

Global River Basins

We have represented the water at the scale of major river basins. Currently 235 global river basins are represented in GCAM. The full list of major river basins included in GCAM is shown in Table 1. Each of the GCAM regions contains the river basins within its border. In many instances, river basins may overlap across multiple GCAM regions where water resources are shared. A few remote basins without water demand representations, such as Antarctica, are not actively modeled.

Table 1. Major Water Basins in GCAM

id name id name id name id name id name
1 Arctic Ocean Islands 51 Japan 101 Caribbean 151 Lake Chad 201 New Zealand
2 Northwest Territories 52 Caspian Sea-East Coast 102 Hamun-i-Mashkel 152 Senegal 202 Australia-South Coast
3 Siberia-North Coast 53 Don 103 Taiwan 153 Cauvery 203 Mar Chiquita
4 Siberia-West Coast 54 Danube 104 Arabian Sea Coast 154 Sri Lanka 204 South Africa-West Coast
5 Kara Sea Coast 55 Adriatic Sea-Greece-Black Sea Coast 105 North Gulf 155 India South Coast 205 Salinas Grandes
6 Lena 56 Ob 106 Yangtze 156 Orinoco 206 La Plata
7 Pacific and Arctic Coast 57 Po 107 Sabarmati 157 Colombia-Ecuador-Pacific Coast 207 North Chile-Pacific Coast
8 Scandinavia-North Coast 58 Amu Darya 108 Xun Jiang 158 Palau and East Indonesia 208 Murray-Darling
9 Russia-Barents Sea Coast 59 Italy-West Coast 109 Hong-Red River 159 North Borneo Coast 209 Pampas Region
10 Mackenzie 60 Spain-Portugal-Atlantic Coast 110 Ganges-Bramaputra 160 Volta 210 North Argentina-South Atlantic Coast
11 Iceland 61 France-South Coast 111 Yucatan Peninsula 161 Northeast South America-South Atlantic Coast 211 Tasmania
12 Sweden 62 Rhone 112 South China Sea Coast 162 Gulf of Guinea 212 South America-Colorado
13 Finland 63 Mediterranean Sea Islands 113 Mahi 163 Sumatra 213 Negro
14 Northern Dvina 64 Gironde 114 Mexico-Interior 164 Sulawesi 214 Central Patagonia Highlands
15 Hudson Bay Coast 65 North and South Korea 115 Pacific Central Coast 165 Kalimantan 215 South Argentina-South Atlantic Coast
16 Scotland 66 Bo Hai-Korean Bay-North Coast 116 Bay of Bengal-North East Coast 166 Magdalena 216 Antarctica
17 Neva 67 Spain-South and East Coast 117 Tapti 167 Irian Jaya Coast 217 California River
18 Volga 68 Lake Balkash 118 Yasai 168 Amazon 218 Upper Mississippi
19 Atlantic Ocean Seaboard 69 Tiber 119 Philippines 169 South Chile-Pacific Coast 219 Lower Mississippi River
20 Baltic Sea Coast 70 Black Sea-South Coast 120 Brahamani 170 Shebelli-Juba 220 Upper Colorado River
21 Denmark-Germany Coast 71 Tagus 121 North Marina Islands and Guam 171 Africa-East Central Coast 221 Lower Colorado River
22 Narva 72 Caspian Sea-South West Coast 122 Mahandi 172 North Brazil-South Atlantic Coast 222 Great
23 Saskatchewan-Nelson 73 Ebro 123 Godavari 173 Papua New Guinea Coast 223 Missouri River
24 Ireland 74 Douro 124 Hainan 174 Tocantins 224 Arkansas White Red
25 Daugava 75 Mediterranean Sea-East Coast 125 Mekong 175 Java-Timor 225 Texas Gulf Coast
26 England and Wales 76 Syr Darya 126 Viet Nam-Coast 176 Solomon Islands 226 South Atlantic Gulf
27 Fraser 77 Ziya He-Interior 127 Salween 177 Madasgacar 227 Great Lakes
28 Ems-Weser 78 China Coast 128 India North East Coast 178 Sepik 228 Ohio River
29 Oder 79 Huang He 129 India West Coast 179 Rift Valley 229 Pacific Northwest
30 Wisla 80 Mediterranean South Coast 130 Papaloapan 180 Peru-Pacific Coast 230 Tennessee River
31 Elbe 81 Guadiana 131 Rio Lerma 181 Fly 231 Rio Grande River
32 Rhine 82 Central Iran 132 Rio Verde 182 Angola-Coast 232 New England
33 Poland Coast 83 Guadalquivir 133 Grijalva-Usumacinta 183 Congo 233 Mid Atlantic
34 Churchill 84 Tigris-Euphrates 134 Rio Balsas 184 Australia-North Coast 234 Hawaii
35 Neman 85 Tarim Interior 135 Southern Central America 185 South Pacific Islands 235 Narmada
36 Scheldt 86 Africa-North West Coast 136 Isthmus of Tehuantepec 186 East Brazil-South Atlantic Coast    
37 Russia-South East Coast 87 Nile 137 Irrawaddy 187 Parnaiba    
38 Ural 88 Persian Gulf Coast 138 Sittang 188 Zambezi    
39 Dnieper 89 Indus 139 Peninsula Malaysia 189 Australia-East Coast    
40 St Lawrence 90 Farahrud 140 Krishna 190 Africa-Indian Ocean Coast    
41 France-West Coast 91 Baja California 141 Andaman-Nicobar Islands 191 Australia-West Coast    
42 Gobi Interior 92 Plateau of Tibet Interior 142 Africa-West Coast 192 Sao Francisco    
43 Amur 93 Red Sea-East Coast 143 Caribbean Coast 193 Australia-Interior    
44 Loire 94 Arabian Peninsula 144 Africa-North Interior 194 Orange    
45 Caspian Sea Coast 95 Dead Sea 145 India East Coast 195 Uruguay-Brazil-South Atlantic Coast    
46 Seine 96 Mexico-Northwest Coast 146 Chao Phraya 196 Namibia-Coast    
47 Black Sea-North Coast 97 Helmand 147 Pennar 197 Africa-South Interior    
48 Yenisey 98 Sinai Peninsula 148 Gulf of Thailand Coast 198 South Africa-South Coast    
49 Dniester 99 Eastern Jordan-Syria 149 Niger 199 Limpopo    
50 Italy-East Coast 100 Africa-Red Sea-Gulf of Aden Coast 150 Micronesia 200 La Puna Region    


Global Land Units

For GCAM3.0 through GCAM4.4, the Agriculture and Land Use model subdivided the GCAM geopolitical regions into as many as 18 climatically defined agro-ecological zones (AEZs) developed by the GTAP group. GCAM5+ switches subregions to water basin-defined geographic land units (GLUs). The land data system files are produced by the Moirai, described in Di Vittorio et al. (2016).

Temporal Resolution

Historical Years

The GCAM data system can produce such data sets annually beginning in 1971. Currently, GCAM uses data from 1990, 2005, 2010, and 2015 to initialize the model, but could be initialized to any year beginning in 1971.

Future Years

Currently, GCAM models the future from 2020 to 2100 in 5 year time steps. The time step is variable and can be changed in the data system.

Economic Choice

GCAM represents choices among options using a logit function. For more information on economic choice, see choice.