365 Days of Climate Awareness 268 - Mexico and Climate Change

Sorry for the late post!  I head out early tomorrow morning for work, so yesterday and last night was all about my kids. I make no apology.

Köppen-Geiger climate zones, 1980-2016

Predicted Köppen-Geiger climate zones, 2071-2100

Several patterns of climate change in Mexico will be very familiar in the context of a tropical climate: more intense and longer dry seasons, and wet seasons which might yield more rain on average, but will do so more erratically, with more violent downpours interspersed with increasingly frequent droughts. In a country as richly biodiverse as Mexico, changing climate patterns will have widespread and thorough effects on the biome, incurring changes in plant and animal species.

Annual CO2 emissions, Mexico.

Cumulative CO2 emissions, Mexico.

Mexico’s economy is ranked 15th in the world, at $1.3T/$91.8T, or 1.4%. Mexico’s share of carbon emissions is almost identical by percentage, at 1.3%. Mexico is one of the countries with mid-sized economies (if at the high end of that range) caught in the pincers of trying to encourage economic development, at the same time that that development is contributing to known damage to its population and economy. All too often now the road of economic development is pursued with little or no regard to the environmental costs, under the faith that later adaptation will mend the problem. Mexican policy of recent years exemplifies this self-destructive behavior, but it is following powerful models in the United States and other much larger economies.

Per capita CO2 emissions, Mexico.

Mexico's climate performance, per Climate Action Tracker.

Rising temperatures are already affecting agriculture in the central and southern zones, including the Yucatán Peninsula. Wheat crops are declining by as much as 60% in some villages as soils increasingly dry out. Similarly, yields of maize, one of Mexico’s staple crops, are expected to drop by 7% by 2050 due to increasing heat and drought, while the number of varieties declines due to environmental stress. Similar effects are expected in coffee bean production. 

Tomorrow: introduction to Greenland.

Be brave, and be well.

365 Days of Climate Awareness 267 - Introduction to Mexico

Mexico is a country in North America covering 1,972,550 sq km/761,610 sq mi with a population of slightly over 126 million. It is bordered by the United States to the north, by Belize and Guatemala to the south, the Gulf of Mexico and the Caribbean Sea to the east, and the Pacific Ocean to the west. It ranges in latitude from 14.5° to 32.6°, making it partly tropical, partly subtropical. Along with ancient China, India, Mesopotamia, Egypt and the Andes, Mexico (Mesoamerica) is considered one of the cradles of world civilization.

New Spain (i.e. Mexico), 1819.

Traces of human habitation stretch back 8,000 years. Many civilizations flourished there, including the Maya and Aztecs, until the Spanish conquistador Hernán Cortés wiped out the Aztecs in 1519-21. The Spanish retained control until 1821, mining silver and exporting it back to Spain, until a Mexican monarchy was established in opposition to foreign rule. Throughout the 19th century Mexico fought repeatedly against the young United States, losing large amounts of territory, and even fended off an invasion by France. (Cinco de Mayo celebrates the Mexican victory in 1862 over the Second French Empire in the Battle of Puebla.) By the end of the 1800’s a republican form of government had emerged, and even though its existence was turbulent, and its politics marred by several murders, Mexican democracy has stood for more than a century.

Modern Mexico, political map.

Ethnically Mexico is still almost one-quarter indigenous, despite the huge loss of population during the epidemics imported by invading Spaniards. Census tracking of ethnicities there has been spotty through the years, but more recently, more detailed categories of local ethnic groups have come into use and counts are sharpening. Climatically Mexico ranges from tropical rainforest, monsoonal and savanna zones in the south to more temperate alpine zones in the central region, to deserts both hot and cool to the north.

Physical map.

The abundance of silver and Mexico’s unique position with coasts on both Atlantic and Pacific–a geopolitical advantage central to the United States’ current global ascendancy–made the Mexican economy, under Spain, a global influence. Mexican pesos served as the world’s defacto first global currency. With independence came multiple wars, civil and external, which contributed to the country’s fall from the global economic stage, particularly as the United States to the north steadily expanded westward and annexed much of Mexico’s former territory, including California and Texas. 

Köppen-Geiger climate zones, 1980-2016

Oil has come to replace silver as Mexico’s prime export. In 1938 Mexico nationalized the international companies drilling for and producing oil there, with predictable effects in drying up investment and limiting the economic benefits of production to a very few. Only recently has Mexican government reopened energy production to a more competitive market, but Mexico’s oil production has been declining, since a maximum of roughly 3.3 million b/day (mmbl) in 2005 to roughly 2.5 mmbl in 2021. About one-third of Mexico’s tax revenues come from the national oil company, PEMEX. 

Mexican oil production (1 TWh ~ 600K barrels of oil)

Though Mexico’s economy has diversified greatly, with automotive and technology sectors becoming increasingly important for exports, income and wealth remain highly stratified, and the still-flourishing drug trade makes law enforcement in some parts of the country tenuous at best. The power and prevalence of drug cartels throughout the country have negatively impacted the tourist industry, another significant source of income for citizens and government alike.

Mexico City.

Tomorrow: Mexico and climate change.

Be brave, and be well.

365 Days of Climate Awareness 266 - The Caribbean and Climate Change

Climate change is already impacting the islands and marine environment of the Caribbean Sea, and will continue to do so, more strongly, in decades to come. Increasing extremes, both in weather events and in general climatic patterns, will weaken ecosystems as they exist now and lead to species change. Agriculture and fisheries have already been negatively affected, and those effects are likely to become more severe.

Köppen-Geiger climate zones, 1980-2016

Predicted Köppen-Geiger climate zones, 2071-2100

The Intergovernmental Panel on Climate Change (IPCC), the world authority on climate change science, has found only medium confidence that the frequency and severity of tropical cyclones are increasing. However, recent NOAA work has found the Atlantic basin to be a growing global hotspot for cyclones and hurricanes, with a slowly increasing number of annual named storms. 

Global hurricane trends

Atlantic basin cyclone trends.

Storm activity, analogously to sea ice extent, is a very noisy signal, with large year-to-year variations. Climate models agree strongly with the more tentative conclusions of storm counts and energy measurements: the Caribbean is likely to receive more of these cataclysmic storm events in years to come as the world warms. An increase of 2°C/3.6°F will increase storm activity in the Caribbean by as much as four times, some models predict.

Threat levels to Caribbean coral reefs

Sea level rise has increased coastal erosion around many Caribbean islands, a trend which will continue. And in the now-familiar pattern throughout the world’s tropical regions, dry seasons have become drier, and will become drier still; while rainy seasons, though the total amount of rain might increase, will occur in fewer, more intense bursts, and more erratically. Economically, most of the Caribbean nations having been colonies until relatively recent (20th century or slightly earlier) times, their economies are not well-developed or robust enough to deal with the disruption of changing climate patterns and increased storm activity. On the contrary, the ruinous cycle of disaster followed by increased debt load has become the norm.

Jamaican banana plantation after Hurricane Sandy, 2012.

Warming, acidifying oceans pose an existential threat to the region’s 10,000 sq km/3,900 sq mi of coral reefs, 22,000 sq km/8,500 sq mi of mangrove and 33,000 sq km/12,700 sq mi of seagrass beds. In many regions of the Caribbean (such as the south coast of Jamaica) already the reefs are dead, more from human agency (overfishing) than purely climate-related causes. But warming water has caused widespread bleaching and led to invasion by highly destructive species of algae, which prevent fresh coral growth and over time kill the reef community. It has been estimated that up to 60% of the Caribbean’s coral reefs have died due to overfishing and interrelated climate causes such as storm activity, warming and acidifying water.

Tomorrow: introduction to Mexico.

Be brave, and be well.

365 Days of Climate Awareness 265 - Introduction to the Caribbean

The Caribbean Sea is a semi-enclosed portion of the Atlantic Ocean bordered by South and Central America to the south and west, and to the north by the Greater (including Cuba) and Lesser Antilles. It is entirely tropical, ranging from 9°-22°N, and 60°-89°W, and covers 2,754,000 sq km/1,063,000 sq mi. It contains 13 countries, more than 700 islands, and a population of about 45 million. 

Political map of the Caribbean

It takes its name from the native Carib tribe (also known as the Kalinago), which predominated throughout the Lesser Antilles when Columbus came upon them in 1492. Then began several centuries of intense and frequently bloody competition between European nations for colonial dominance. The English in particular brought in slaves from Africa, so the natives found themselves being displaced, sometimes gradually and sometimes aggressively, by white Europeans and black slaves. Today, ethnic strains of the natives still exist, and the Kalinago maintain a distinct national identity, with a reservation in Dominica (not to be confused with the Dominican Republic).

Physical map of the Caribbean.

The main economic product of the region is tourism. Some countries like Jamaica feature tourist enclaves on the main island almost entirely cut off from the native population. Others, like Trinidad and Tobago, have fostered their tourist industry on the smaller, less populated islands (Tobago in that case). Their economies suffered terribly from the COVID pandemic, contracting a collective 8.6% in 2020. and Trinidad produces nearly 100,000 barrels of oil a day from its offshore fields–a significant amount, ranking it 50th in the world among oil producers. Agricultural production, including sugarcane, bananas, cocoa and coffee, is a significant part of most Caribbean nations’ GDP.

Tectonic plates.

The Caribbean region is very active tectonically, being located over a small tectonic plate bordered by the North and South American plates to the east, and the smaller plates to the west (Cocos, Panama, and North Andes). These plates are either subducting–with one oceanic plate diving beneath another, creating volcanoes and earthquakes–or transform, where the plates slide past each other, generating large earthquakes (like the San Andreas in California). Volcanic eruptions and large quakes are common enough that the region is on constant alert for them, and some nations like Haiti and the Dominican Republic–which share one island–have been struck repeatedly in recent years.

Main Development Region (MDR) of Atlantic cyclones.

The eastern half of the Caribbean is part of the Main Development Region for Atlantic cyclones. Powerful summer and fall storms are a terrible and recurrent part of life there. One storm can wipe out the entire crop on an island, such as how in 2007 Hurricane Dean destroyed 100% of Jamaica’s banana crop and badly damaged the coffee and sugarcane crops. An unfortunate side-effect, beyond the destruction of homes, infrastructure and livelihoods, is that repair and restoration after major events often becomes a fresh load of debt for the small, already-struggling governments.

Tomorrow: the Caribbean and climate change.

Be brave, and be well.

365 Days of Climate Awareness 264 - The Panama Canal and Climate Change

The Panama Canal, which connects the Atlantic and Pacific Oceans via the Isthmus of Panama, is the conduit to an estimated 3% of world trade (by comparison, 12% runs through the Suez), cutting the trip around South America by weeks. It is 82 km/51 mi long and was begun in 1888 by France, but when investor confidence faltered after many worker deaths, the United States too over in 1904, completing the project in 1914. In 1999 the nation of Panama took full control of the canal’s operation, though, in competition with China, the United States maintains the power by treaty to defend it against any influence which would seek to close it off to any innocent (i.e. commercial) traffic.

The Isthmus of Panama.

Among the many challenges were the mountainous terrain, requiring ships to be lifted as much as 25 m/85 ft above sea level through a series of gravity-fed locks, and dropping them down again on the other side of the isthmus (where the Atlantic and Pacific ocean levels differ mostly due to tides, which are larger on the Pacific side). The locks are basically dams, through which water is allowed to flow under control and so gently raise or lower the ships in transit. Building this lock system created the gigantic Lake Gatún, which is the central part of the canal passage.

Map of the canal.

Lake Gatún is the source of water for the lower locks, and normally has no trouble meeting the canal’s transit needs. However, in 2019, a strong El Niňo brought a drought of more than five months which lowered lake levels to the point that the Panamanian authority restricted travel through the canal until Gatún was sufficiently replenished. That has led to debates within Panama about creating more artificial lakes, to serve as water reserves. Environmentalists are firmly against this plan, saying that the trade of forest for artificial lake is inherently bad. The likelihood of increasingly strong El Niňo events in the coming century threatens to put the use of the canal at risk.

Cross section of the canal.

Compared to transit around Cape Horn on South America’s tip it is claimed that the Panama Canal reduced carbon emissions by more than 13 million tons in 2020. While economizing is good, the larger issue is the general growth of the economy which these efficiencies empower. Another example is America’s interstate highways, which after their creation in the 50’s and 60’s were objects of amazement, allowing fast, easy travel across the country. Specifically, California’s highways in the early 60’s brought about a new way of life. But within a decade, the number of cars and drivers on those same highways had risen to a level where horrendous traffic jams and dangerous levels of pollution were commonplace. 

Lake Gatún.

So with the Panama Canal: the current canal, with modern efficiencies, carries more than four times the ship tonnage it was originally designed for, and has become an integral part of a world economy which has grown sixteen times larger ($81T vs. $5T global GDP) since the canal first opened (3% of $81T is $2.4T, nearly half the 1914 world economy). Of course the Panama Canal is not responsible for the world’s entire economic growth. But it is intertwined, and simply citing modern efficiencies is far from understanding its role in facilitating greenhouse gas emissions worldwide. One crude measure is by global CO2 emissions, which were 31.5 GT in 2020: 3% of this, 945 MT, represents trade which passed through the Panama Canal that year. This is not to condemn the use of the canal: it is to emphasize, however, that efficiencies are worthwhile only when applied wisely, not used as an attempted shortcut around nature.

Gaillard Cut, Lake Gatún.

Tomorrow: introduction to the Caribbean.

Be brave, and be well.

365 Days of Climate Awareness 263 - Central America and Climate Change

While sea level rise poses a threat to all coastal states, and temperature rise has and will continue to contribute to changing ecosystems, in this tropical zone the major threat from climate change is in “global weirding”, the increasing frequency and severity of extreme weather events, including tropical cyclones, extreme rainfall and drought. Though the entire region is classified as having a medium-level economy, national economies vary in strength and stability, from Guatemala (largest) and Panama to Honduras and Nicaragua. In per capita annual income, after Costa Rica ($9500), Central American countries are at roughly $4000 or below.

Köppen-Geiger climate zones, 1980 - 2016

Köppen-Geiger climate zones, 2071-2100

Emigration from Central America has increased in recent decades, due to economic hardship, violence, and, in a growing trend, as a result of environmental disasters such as persistent drought. A recent survey of asylum-seeking immigrants to the US showed economic anxiety and food insecurity as the dominant concern (92%). Environmental factors were very minor–noted by only 6%, along with violence, at 5%--but it is absolutely the case that many of these concerns overlap when large-scale disruption of the environment and economy occurs.

The Northern Triangle.

Central America’s Northern Triangle (Guatemala, Honduras and El Salvador) is the source of most emigration from the region, with an estimated 407,000 coming northward between 2018 and 2021. A recent crippling drought in the region combined with two historically strong 2020 hurricanes, Eta and Iota, to drive increased numbers of refugees north. Poor nations in environmentally precarious positions–Central America being an active seismic and volcanic zone, subject to frequent tropical cyclones, and with an arid region known as the “Dry Corridor” spanning it from north to south certainly qualifies–have tended, and will continue, to produce most climate refugees as the global warming crisis intensifies. 

The Dry Corridor.

This area of the world is immensely complex, both societally, environmentally and in other ways. Climate models predict the Dry Corridor to expand, though not greatly. Though statistical analysis of tropical cyclone strength and frequency has yielded only medium confidence in their increase due to global warming, it is in the combination of factors–sea level rise, plus drought, plus storm activity–that ruinous effects of climate change are already being felt in sensitive regions like Central America. Models show trends toward increasingly extreme weather events increasing in decades to come.

Tomorrow: the Panama Canal and global warming.

Be brave, and be well.

365 Days of Climate Awareness 262 - Introduction to Central America

Central America is the narrow portion of North America between Mexico and Colombia. It consists of seven countries (Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica and Panama). From Mexico it extends southward along tectonic boundaries between the Cocos and Nazca plates to the southwest, and the Caribbean plate to the northeast. It is entirely tropical, ranging between roughly 13° and 7.5° N latitude, and a population of slightly over 45 million. Central America forms a land bridge between the continental masses of North America (which it is considered part of), and South America, with its narrowest point about 50 km/30 mi wide, occurring at the Isthmus of Panama.

Political map.

Academic debate has seesawed for some time on when Central America became a complete land bridge blocking Pacific from Atlantic water. Consensus thinking is that this led to the formation of the Gulf Stream and the current North Atlantic climatic regime, in addition to the ice ages of the past 2-3 million years tied to the Earth’s Milankovitch cycles. Several different lines of evidence, including fossils and sediment cores from the Pacific and Caribbean leave a fairly wide window for this to have happened, from almost six to about 2.5 million years ago. Currently the Isthmus is crossed by the Panama Canal, though this is of no relevance to ocean currents.

Physical map.

The region is tectonically very active, with two oceanic plates–the Cocos to the north, and the Nazca to the south–moving northeastward and being subducted beneath the Caribbean and South American plates. Volcanoes and earthquakes are regular occurrences there. On top of this, the region frequently receives tropical cyclones, from depressions on up to hurricanes, on an annual basis. Despite the dynamic geological and climatic environment, Central America is one of the most biodiverse spots on earth, estimated to contain 7% of the planet’s entire biodiversity (number of distinct species). 

Tectonic plates of Central America and the Caribbean.

Evidence of human inhabitation stretches back more than 12,000 years. The region came to be dominated by the Maya from the south and the Aztecs from the north, though the arrival of the Spanish in the early 1500’s signaled the era of colonial domination and the forced export of mined precious metals and other products. In the 1800’s local populations began asserting their independence, though they seldom found peace with each other, and the Mexicans to the north made repeated attempts to conquer and control their southern neighbors. The modern-day countries we know largely emerged from the ongoing civil wars and attempts at conquest which continued throughout most of the 19th century. 

Köppen-Geiger climate zones, 1980 - 2016

Tomorrow: climate issues facing Central America.

Be brave, and be well.