The human species did not exist the last time CO2 levels in the earth’s atmosphere were sustained at 400 ppm, as they are now. It was 10 to 15 million years ago during the Miocene epoch. The earth then was 12ºC (21ºF) warmer. There was little or no ice in the oceans and sea levels were 100 feet higher.
Since 1950, the average temperature in Antarctica has risen 5º Celsius (9º F) and may rise as much as another 7º Celsius (12º F) by the end of the century, which would equal the temperature during the Miocene. Consequently, the ice is on its way to a Miocene-like low with a inversely proportional rise in sea levels.
A Big Splash
Scientist are at this time anxiously watching a rapidly growing crack in the Larsen C ice shelf. The crack has grown 11 miles in just the past week to 111 miles. The area it bounds is just 8 miles away from breaking off the main shelf. It will be the biggest iceberg ever, the size of the state of Delaware. Enormous though it is, the break-off itself will not significantly affect sea levels. However, it will weaken the main shelf, which is likely to make it collapse further, as did its neighbors Larsen A and B before. And that would indeed make the oceans rise.
Drenched to the Bone
‘Come gather round people wherever you roam and admit that the waters around you have grown’. When Bob Dylan wrote these words half a century ago, he may not have realized how much he himself was prophesying with his pen.
The projected rise in sea levels due to melting sea ice is probably the gravest consequence of the warming trend of the past 2 centuries, because it impacts coastal areas worldwide, regardless of political boundaries or national sovereignty. Indeed, five of the 10 coastal cities most at risk of major flooding are in the US: Miami, New York, New Orleans, Tampa and Boston.
There is a general consensus among scientists and business leaders the world over, as well as the majority of political leaders, that the warming trend is primarily driven by carbon-dioxide emissions from the burning of fossils fuels – coal an oil. The atmospheric dome of CO2 works like a one-way mirror: it lets the sunlight in, but does not let it out, turning the entire earth into a huge green house.
The Paris Climate Agreement
This consensus was substantiated in the Paris Climate Agreement of 2016, which aims to keep global warming under 2ºC (4ºF). It is estimated that without implementation of the Agreement, the rise in temperature will be at least double that. The negotiations were difficult, because none of the 198 participating nations were eager to make the needed fundamental changes to their economic structure – least of all the developing countries, who felt they would be stopped in their tracks just when they got going. But the diplomats managed to come up with a deal, which, until recently, everyone thought fair.
Way to Go
The prospective drop-out is our very own US of A, the second largest emitter of CO2. China is first, but they are making a titanic effort to reduce their output, in the process becoming the world leader in the development of alternative energy sources. While they are moving toward the future, we seem to be receding into the smog of the past. Then it may come true that the first one now will later be last.
However, it can take four years before withdrawal of the US from the Paris Climate Accord passes all the legal and political hurdles. Ultimately, then, the matter may be decided by the people – at least the people who vote.
(Broadcast 4:04)
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