Scientists and economists are beginning to consider the serious economic and environmental consequences if we fail to reduce global carbon emissions quickly. The most expensive thing we can do is nothing.
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The cost of global warming: damage to property and infrastructure is real.
Sea-level rises, floods, droughts, wildfires, and extreme storms require expensive repairs of essential infrastructure such as homes, roads, bridges, railroad tracks, airport runways, power lines, dams, levees, and seawalls.
Disruptions in daily life related to climate change can lead to loss of work and school days and can harm trade, transportation, agriculture, fisheries, energy production, and tourism. Heavy rainfall and snowstorms can delay planting of crops on farms and harvesting, and can cause loss of electricity supply, traffic jams, and delays at airports. Climate change can also cause health risks which also reduce productivity.
Global warming is likely to increase the number of “climate refugees” — people who are forced to leave their homes because of drought, flooding, or other climate-related disasters. Migration of people may lead to conflict, and might even lead to war.
Societies may find ways to prepare for and cope with some climate impacts. However, coping is likely to be more expensive than steps to reduce carbon emissions.
For example, farmers might need to irrigate areas that used to receive rain, they will need to keep animals cool, and they will have to stop more pests and diseases. Governments spend money making sure that houses are more energy efficient, and build early warning systems for heat waves and disasters and build more emergency services. Governments may also have to build seawalls, stop sewer overflows, and make bridges and subways stronger.
However, rebuilding after disasters is likely to be even more costly than preparing for the disasters. And these costs do not include deaths and consequences which cannot be reversed.
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Global travel discovery: The Great Ocean Conveyer Belt
The oceans are in constant motion both from winds that generate waves and currents and from the pull of gravity that creates the tides. Another factor that is not as well-known is thermohaline circulation or the ‘Great Ocean Conveyer Belt’. This movement of water acts like a conveyor belt because oceans move huge amounts of the Sun’s heat around the world. Without this, places at the same latitude across the world would generally have the same average temperatures. However, because of this circulation, Norway, which is located at similar latitude to Manitoba, Canada, has an average annual temperature that is nearly 20°F warmer.
The movement of the Great Ocean Conveyor Belt is caused by changes in the density of sea water. The conveyor belt moves warm water from the Pacific Ocean to the Atlantic as a shallow current and returns cold water from the Atlantic to the Pacific as a deep current that flows further south. Beginning in the central Pacific, it travels past the north coast of Australia and around the southern tip of Africa before moving up into the Atlantic. By the time it goes up the Atlantic it joins what is called the Gulf Stream (another movement of warm water). As it passes Europe, it releases heat, making Western Europe relatively warm. As the water reaches Greenland, it becomes colder. It also becomes saltier (because the Atlantic Ocean is saltier than the Pacific Ocean. Because cold salt water sinks, the Great Ocean Conveyor belt sinks downwards thousands of meters below the surface off the coast of Greenland. This deep cold water slowly travels back south along the bottom of the ocean, eventually mixing upward to the surface in different parts of the world up to 1,000 years later.
The Great Ocean Conveyor Belt plays an important role in the Earth’s climate. However, global climate changes could alter, or even halt, this current. As the Earth becomes hotter, there could be an increase in rain and snow and the freshwater ice in the Arctic Ocean could melt which would flow into the Atlantic Ocean. This additional freshwater could make the Atlantic less salty and it might not continue to sink and return to the Pacific. If this happened the Great Ocean Conveyor Belt might stop and Europe would become much colder.
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Global travel learning: Glacial-Interglacial Climate Cycles
Throughout earth’s history, major ice ages (glacials) have occurred over and over again. Ten of them affected the planet in the past one million years and another ten in the million or so years before that. Each one lasts for about 90,000 years, after which it is followed by a 10,000-year interglacial (warm period). We are currently living in an interglacial. Our Interglacial is about 10,800 years old.
We do not have a lot of understanding of the climate during glacial-interglacial cycles, but new studies are providing us with more information about the topic. This growing information is helpful, for it gives us a long history to compare the current climate with and to see if it is unique.
It has been claimed by some scientists, for example, that the continuing rise in the amount of CO2 in the air actually made the 1990s the warmest period of the entire past million years (Mann et al., 1998, 1999). “Unprecedented” is the word that supporters of this idea frequently use to describe the current temperature of the globe. However, this is simply not true, and, in fact, when the average temperature of the 1990s is compared with the warmest temperatures of the last four interglacials (which we have excellent temperature records for), the 1990s are found to have been much cooler than all of these other periods.
For example, a temperature history made from the Vostok ice core in East Antarctica that covers the past 420,000 years determined that “the temperature … [238,000 years ago] was slightly warmer than the Holocene [the current interglacial].” It also noted that the interglacials before and after the one at 238,000 years ago were even warmer. In fact, it can be seen that all of the last four interglacials were warmer than the current one by an average temperature in excess of 2°C.
Similar discoveries have been found from the Dome Fuji ice core, which was taken from a site in an entirely different part of East Antarctica that is separated from the Vostok ice-core site by 1500 km (Watanabe et al., 2003). Although this study only covered the last three glacial-interglacial periods, it also reveals that the last three interglacial “were much warmer than the most recent 1,000 years (from 4.5°C – 6°C).”
Thus, over the past half-million years, it is clear that the average air temperature of the earth during the 1990s was not unusually warm, but unusually cool. And not even the much greater amounts of atmospheric CO2 were able to change this. This leads to an interesting question. Do current temperatures and climate show human interference? Clearly, they do not.
“A study of an ice core from a mountain range in northwest Greece has revealed that the last great glacial period (ice age) started about 10,800 years after the beginning of the last interglacial period (Frogley et al., 1999).”
