Geography of Mexico

Mountain ranges and elevations Beginning approximately from the United States border, the Sierra Madre Occidental mountain range extends about south to the Río Santiago, where it merges with the Cordillera Neovolcánica range that runs east–west across central Mexico. The Sierra Madre Occidental lies approximately inland from the west coast of Mexico at its northern end, and approaches to within fifty kilometers of the coast near the Cordillera Neovolcánica. The northwest coastal plain is the name given the lowland area between the Sierra Madre Occidental and the Gulf of California. The Sierra Madre Occidental averages in elevation, with peaks reaching . mountain near Mexico City. It is characterized by its snow-capped summit and rugged terrain, including steep slopes and glaciers. , also known as Citlaltépetl, is the highest mountain in Mexico and the third highest peak in North America, after Denali in Alaska and Mount Logan in Canada. The Sierra Madre Oriental mountain range starts at the Big Bend region of the border with the U.S. state of Texas and continues until reaching Cofre de Perote, one of the major peaks of the Cordillera Neovolcánica. As is the case with the Sierra Madre Occidental, the Sierra Madre Oriental comes progressively closer to the coastline as it approaches its southern terminus, reaching to within of the Gulf of Mexico. The northeast coastal plain extends from the eastern slope of the Sierra Madre Oriental to the Gulf of Mexico. The median elevation of the Sierra Madre Oriental is , with some peaks at . The Mexican Altiplano, stretching from the United States border to the Cordillera Neovolcánica, occupies the vast expanse of land between the eastern and western sierra madres. A low east–west range divides the altiplano into northern and southern sections. These two sections, previously called the Mesa del Norte and Mesa Central, are now regarded by geographers as sections of one altiplano. The northern altiplano averages 1,100 meters in elevation and continues south from the Río Bravo del Norte through the states of Zacatecas and San Luis Potosí. Narrow, isolated ridges cross the plateaus of the northern altiplano. Numerous depressions dot the region, the largest of which is the Bolsón de Mapimí. The southern Altiplano is higher than its northern counterpart, averaging in elevation. The southern altiplano contains numerous valleys originally formed by ancient lakes. Several of Mexico's most prominent cities, including Mexico City and Guadalajara, are located in the valleys of the southern Altiplano. that do not drain to the sea. One other significant mountain range, the Peninsular Ranges, cuts across the landscape of the northern half of Mexico. A southern extension of the California coastal ranges that parallel California's coast, the Mexican portion of the Peninsular Ranges extends from the United States border to the southern tip of the Baja California Peninsula, a distance of . Peaks in the California system range in altitude from in the north to only near La Paz in the south. Narrow lowlands are found on the Pacific Ocean and the Gulf of California sides of the mountains. The Cordillera Neovolcánica is a belt long and wide, extending from the Pacific Ocean to the Gulf of Mexico. The Cordillera Neovolcánica begins at the Río Grande de Santiago and continues south to Colima, where it turns east along the nineteenth parallel to the central portion of the state of Veracruz. The region is distinguished by considerable seismic activity and contains Mexico's highest volcanic peaks. This range contains three peaks exceeding : Pico de Orizaba (Citlaltépetl)—the third highest mountain in North America—and Popocatépetl and Iztaccíhuatl near Mexico City. The Cordillera Neovolcánica is regarded as the geological dividing line between North America and Central America. Several important mountain ranges dominate the landscape of southern and southeastern Mexico. The Sierra Madre del Sur extends 1,200 kilometers along Mexico's southern coast from the southwestern part of the Cordillera Neovolcánica to the nearly flat isthmus of Tehuantepec. Mountains in this range average 2,000 meters in elevation. The range averages 100 kilometers wide, but widens to 150 kilometers in the state of Oaxaca. The narrow southwest coastal plain extends from the Sierra Madre del Sur to the Pacific Ocean. The Sierra Madre de Oaxaca begins at Pico de Orizaba and extends in a southeasterly direction for 300 kilometers until reaching the isthmus of Tehuantepec. Peaks in the Sierra Madre de Oaxaca average 2,500 meters in elevation, with some peaks exceeding 3,000 meters. South of the isthmus of Tehuantepec, the Sierra Madre de Chiapas runs 280 kilometers along the Pacific Coast from the Oaxaca-Chiapas border to Mexico's border with Guatemala. Although average elevation is only 1,500 meters, one peak—Volcán de Tacuma—exceeds 4,000 meters in elevation. The Meseta Central de Chiapas extends 250 kilometers through the central part of Chiapas to Guatemala. The average height of peaks of the Meseta Central de Chiapas is 2,000 meters. The Chiapas central valley separates the Meseta Central de Chiapas and the Sierra Madre de Chiapas. Rivers and other bodies of water , Mexico's largest freshwater lake. Mexico has nearly 150 rivers, two-thirds of which empty into the Pacific Ocean and the remainder of which flow into the Gulf of Mexico or the Caribbean Sea. Despite this apparent abundance of water, water volume is unevenly distributed throughout the country. Indeed, five rivers—the Usumacinta, Grijalva, Papaloapán, Coatzacoalcos, and Pánuco—account for 52 percent of Mexico's average annual volume of surface water. All five rivers flow into the Gulf of Mexico. Only the Río Pánuco is outside southeastern Mexico, which contains approximately 15 percent of national territory and 12 percent of the national population. In contrast, northern and central Mexico, with 47 percent of the national area and almost 60 percent of Mexico's population, have less than 10 percent of the country's water resources. In 2024, a team of oceanographers discovered the world's deepest blue hole, Taam Ja, meaning 'deep waters' in Mayan, in Chetumal Bay, Mexico. Due to technical limitations, the actual depth of the hole is still unknown. The findings suggest the presence of a complex labyrinth of underground caves and tunnels, which could shed new light on the site and the diversity of life within it. ==Seismic activity==

Situated atop three of the large tectonic plates that constitute the Earth's surface, Mexico is one of the most seismologically active regions on Earth. The motion of these plates causes earthquakes and volcanic activity. Most of the Mexican landmass rests on the westward moving North American plate. The Pacific Ocean floor off southern Mexico, however, is being carried northeast by the underlying motion of the Cocos Plate. Ocean floor material is relatively dense; when it strikes the lighter granite of the Mexican landmass, the ocean floor is forced under the landmass, creating the deep Middle America Trench that lies off Mexico's southern coast. The westward moving land atop the North American plate is slowed and crumpled where it meets the Cocos plate, creating the mountain ranges of southern Mexico. The subduction of the Cocos plate accounts for the frequency of earthquakes near Mexico's southern coast. As the rocks constituting the ocean floor are forced down, they melt, and the molten material is forced up through weaknesses in the surface rock, creating the volcanoes in the Cordillera Neovolcánica across central Mexico. Areas of Mexico's coastline on the Gulf of California, including the Baja California Peninsula, are riding northwestward on the Pacific plate. Rather than one plate subducting, the Pacific and North American plates grind past each other, creating a slip fault that is the southern extension of the San Andreas Fault in California. Motion along this fault in the past pulled Baja California away from the coast, creating the Gulf of California. Continued motion along this fault is the source of earthquakes in western Mexico. Mexico has a long history of destructive earthquakes and volcanic eruptions. In September 1985, an earthquake measuring 8.0 on the moment magnitude scale and centered in the subduction zone off Acapulco killed more than 4,000 people in Mexico City, more than 300 kilometers away. Volcán de Colima, south of Guadalajara, erupted in 1994, and El Chichón, in southern Mexico, underwent a violent eruption in 1983. Parícutin in northwest Mexico began as puffs of smoke in a cornfield in 1943; a decade later the volcano was 424 meters high. Although dormant for decades, Popocatépetl and Iztaccíhuatl ("smoking warrior" and "white lady," respectively, in Nahuatl) occasionally send out puffs of smoke clearly visible in Mexico City, a reminder to the capital's inhabitants that volcanic activity is near. Popocatépetl showed renewed activity in 1995 and 1996, forcing the evacuation of several nearby villages and causing concern by seismologists and government officials about the effect that a large-scale eruption might have on the heavily populated region nearby. ==Climate==

map of Mexico The Tropic of Cancer effectively divides the country into temperate and tropical zones. Land north of the twenty-fourth parallel experiences cooler temperatures during the winter months. South of the twenty-fourth parallel, temperatures are fairly constant year round and vary solely as a function of elevation. Areas south of the twentieth-fourth parallel with elevations up to (the southern parts of both coastal plains as well as the Yucatán Peninsula), have a yearly median temperature between . Temperatures here remain high throughout the year, with only a difference between winter and summer median temperatures. Although low-lying areas north of the twentieth-fourth parallel are hot and humid during the summer, they generally have lower yearly temperature averages (from ) because of more moderate conditions during the winter. forest in the Sonoran Desert, Mexico. Between , one encounters yearly average temperatures between . Towns and cities at this elevation south of the twenty-fourth parallel have relatively constant, pleasant temperatures throughout the year, whereas more northerly locations experience sizeable seasonal variations. Above , temperatures drop as low as an average yearly range between in the Cordillera Neovolcánica. At , Mexico City has a yearly median temperature of with pleasant summers and mild winters. Average daily highs and lows for May, the warmest month, are , and average daily highs and lows for January, the coldest month, are . Rainfall varies widely both by location and season. Arid or semiarid conditions are encountered in the Baja California Peninsula, the northwestern state of Sonora, the northern altiplano, and also significant portions of the southern altiplano. Rainfall in these regions averages between per year, although even less in some areas, particularly in the state of Baja California. Average rainfall totals are between in most of the major populated areas of the southern altiplano, including Mexico City and Guadalajara. Low-lying areas along the Gulf of Mexico receive in excess of of rainfall in an average year, with the wettest region being the southeastern state of Tabasco, which typically receives approximately of rainfall on an annual basis. Parts of the northern altiplano, highlands and high peaks in the Sierra Madres receive yearly snowfall. Citlaltépetl, Popocatépetl and Iztaccíhuatl continue to support glaciers, the largest of which is the Gran Glaciar Norte. Mexico has pronounced wet and dry seasons. Most of the country experiences a rainy season from June to mid-October and significantly less rain during the remainder of the year. February and July generally are the driest and wettest months, respectively. Mexico City, for example, receives an average of only of rain during February but more than in July. Coastal areas, especially those along the Gulf of Mexico, experience the largest amounts of rain in September. Tabasco typically records more than of rain during that month. A small coastal area of northwestern coastal Mexico around Tijuana has a Mediterranean climate with considerable coastal fog and a rainy season that occurs in winter. Mexico lies squarely within the hurricane belt, and all regions of both coasts are susceptible to these storms from June through November. Hurricanes on the Pacific coast are often less violent than those affecting Mexico's eastern coastline. Several hurricanes per year strike the Caribbean and Gulf of Mexico coastline, however, and these storms bring high winds, heavy rain, extensive damage, and occasional loss of life. Hurricane Gilbert passed directly over Cancún in September 1988, with winds in excess of , producing major damage to hotels in the resort area. It then struck northeast Mexico, where flooding from the heavy rain killed dozens in the Monterrey area and caused extensive damage to livestock and vegetable crops. File:Baja California Desert.jpg|Baja California File:Yucca_decipiens_3.jpg|Shrubs, succulents like Yucca decipiens, and small grasses coexisting in the semi-arid desert of Zacatecas. Part of the Chihuahuan Desert. Climate change ==Environmental conditions==

, on the Mexico–U.S. border Mexico faces significant environmental challenges damaging nearly all sections of the country. Soil destruction is particularly pronounced in the north and northwest, with more than 60% of land considered in a total or accelerated state of erosion. Fragile because of its semiarid and arid character, the soil of the region has become increasingly damaged through excessive cattle-raising and irrigation with waters containing high levels of salinity. The result is a mounting problem of desertification throughout the region. Carmona-Morena et al. 2004 & Sánchez-Medina et al. 2015 find Mexico's environmental enforcement in the tourism sector varies between little and nonexistent. File:Pantanos_de_Centla_2.JPG|The Usumacinta River, in "Tres Brazos" the Usumacinta joins to San Pedrito river and Grijalva river, in the Wetlands of Centla, biosphere reserve, in Tabasco. File:Field_near_San_Miguel_de_Allende.jpg|The Mexican Plateau, also known as the Mexican Altiplano or Mesa Central Deforestation Mexico faces significant environmental challenges damaging nearly all sections of the country. Vast expanses of southern and southeastern tropical forests have been denuded due to mineral resource extraction, and then, far behind in second place, for cattle-raising and agriculture. For example, tropical forests covered almost half of the state of Tabasco in 1940 but less than 10% by the late 1980s. During the same period, pastureland increased from 20 to 60% of the state's total area. Analysts reported similar conditions in other tropical sections of Mexico. Deforestation and desertification has contributed to serious levels of soil erosion nationwide. In 1985 the government classified almost 17% of all land as totally eroded, 31% in an accelerated state of erosion, and 38% demonstrating signs of incipient erosion. Tree cover extent and loss Global Forest Watch publishes annual estimates of tree cover loss and 2000 tree cover extent derived from time-series analysis of Landsat satellite imagery in the Global Forest Change dataset. In this framework, tree cover refers to vegetation taller than 5 m (including natural forests and tree plantations), and tree cover loss is defined as the complete removal of tree cover canopy for a given year, regardless of cause. For Mexico, country statistics report cumulative tree cover loss of from 2001 to 2024 (about 9.8% of its 2000 tree cover area). On the UNFCCC REDD+ Web Platform, Mexico's Warsaw Framework elements are listed as “reported” for its submissions (national strategy, safeguards information, and a national forest monitoring system), and its reference levels are listed as “assessed”. Mexico's first national FREL (submitted in 2014 and assessed in 2015) covered the REDD+ activity “reducing emissions from deforestation” at national scale, expressed as a historical average of CO2 emissions from gross deforestation over 2000–2010. The modified/assessed FREL reported by the technical assessment was 44,388,620 t CO2 eq per year. The assessed FREL included the above-ground and below-ground biomass pools and CO2 only, while excluding litter, dead wood and soil organic carbon (in mineral and organic soils). Mexico submitted an updated national FREL in 2020 (assessed in 2022), with a 2007–2016 historical reference period and an assessed value of 20,245,016 t CO2 eq per year after modification during the technical assessment. This second FREL expanded scope to include emissions from deforestation and a defined subset of forest degradation (“absolute forest degradation”) and expanded pools to include above-ground biomass, below-ground biomass, deadwood and soil organic carbon (while litter was not included). The UNFCCC REDD+ Web Platform also lists Mexico's reported REDD+ results for 2017–2019 (6,041,219 t CO2 eq/year) against the assessed reference level of 20,245,016 t CO2 eq/year, for the reported activities of deforestation and forest degradation. ==General indicators==

Climate: varies from tropical to desert. Terrain: high, rugged mountains; low coastal plains; high plateaus; desert. Elevation extremes: • lowest point: Laguna Salada -10 m • highest point: Pico de Orizaba volcano 5,700 m Natural resources: petroleum, silver, copper, gold, lead, zinc, natural gas and timber. Land use: • arable land: 12.98% • permanent crops: 1.36% • other: 85.66% (2011) Irrigated land: 64,600 km2 (2009) Total renewable water resources: 457.2 km3 Natural hazards: are Nevado de Colima, Parícutin, Popocatépetl, and Pico de Orizaba. Tsunamis and tropical cyclones along the Pacific coast, volcanoes and destructive earthquakes in the center and south, and hurricanes on the Gulf of Mexico and Caribbean coasts. volcanism: volcanic activity in the central-southern part of the country; the volcanoes in Baja California are mostly dormant; Colima (elev. 3,850 m), which erupted in 2010, is Mexico's most active volcano and is responsible for causing periodic evacuations of nearby villagers; it has been deemed a "Decade Volcano" by the International Association of Volcanology and Chemistry of the Earth's Interior, worthy of study due to its explosive history and close proximity to human populations; Popocatepetl (elev. 5,426 m) poses a threat to Mexico City; other historically active volcanoes include Barcena, Ceboruco, El Chichon, Michoacan-Guanajuato, Pico de Orizaba, San Martin, Socorro, and Tacana Environment – current issues: Natural fresh water resources scarce and polluted in north, inaccessible and poor quality in center and extreme southeast; raw sewage and industrial effluents polluting rivers in urban areas; deforestation; widespread erosion; desertification; serious air pollution in the national capital and urban centers along the US-Mexico border; land subsidence in Valley of Mexico caused by groundwater depletion. Environment – international agreements: Party to: biodiversity, climate change, climate change-Kyoto Protocol, desertification, endangered species, hazardous wastes, law of the sea, marine dumping, marine life conservation, lzone layer protection, ship pollution, wetlands, whaling. ==See also==