August was a busy month in the tropics, with hurricanes in the Atlantic and Pacific. The US and China ratified a historic climate agreement, even as floods in Pakistan and Louisiana indicate that atmospheric changes from global warming are already taking place. Let’s go Around The World.
August was a disastrously wet month in Louisiana. Floods caused over eight billion dollars worth of damage from over two feet of rain. The Gulf of Mexico is an infinite source of water, but flooding of this magnitude is unprecedented, and the suspicion is growing that it is connected to global warming.
Parts of southern Pakistan are on the edge of the Indian monsoon, and whereas locations that normally receive up to 100 inches of rain per month can absorb that amount of water, places that normally get only a few inches per month can be inundated with rainfall of 4 inches in a short period of time.
Pakistan’s major city of Karachi received about four and a half inches of rain on August 7 and 8, resulting in tens of casualties and major damage. Authorities can be faulted for paying insufficient attention to infrastructure issues such as proper drainage for rainfall, but in this case the government should be applauded for issuing advisories well in advance of the flooding. In early June, the Pakistan Meteorological Department warned that unusually heavy monsoon rains were likely during the summer and the Prime Minister issued an alert.
August’s epic flooding in Louisiana and Pakistan seems to have the same general cause as many other flooding events in the past few years: Rain that just won’t move and dumps excessive amounts in one spot. This may be the first sign that the general circulation is changing due to greenhouse-gas-induced warming of the planet.
Hurricanes And Hawaii
Two hurricanes gave Hawaii close calls in the past week: Madeline passed to the south and Lester went to the north. Both hurricanes were, at one time, pointed directly at the island chain. Hurricane impacts on Hawaii have been rare in the past, but with water temperatures increasing in the eastern Pacific as elsewhere, the probability of a direct hit is increasing.
Global Warming: A Little Difference Makes A Big Difference
Hawaii has only infrequently been threatened by hurricanes until the last couple of years. Water temperatures were too cool to support powerful tropical storms. But a couple of degrees has made all the difference. The water east and southeast of Hawaii has now reached the critical level of 80 degrees Fahrenheit. The water is likely to get warmer as the earth as a whole warms.
Locations near sea level are already being profoundly affected by the relatively small change in global temperatures. The foot of sea level rise associated with melting glaciers and expanding water volume made the difference between water lapping at the subway entrances and flooding them in Superstorm Sandy.
Inflection points — spots at which a tiny change in some parameter introduces massive changes in others — are common in the universe. Consider Chandrasekahr limit. A perfectly stable white dwarf star slowly accumulates mass from a binary companion. At a certain mass, the star becomes gravitationally unstable and collapses, triggering a supernova. The camel’s back can only support so much weight, and a single straw can break it.
US And China Ratify COP21
The United States and China submitted ratification papers for the Paris climate agreement to the UN on September 3.
Since the two countries account for about 40% of the CO2 emissions worldwide, ratification of the agreement, which requires approval by 55 countries that account for 55% of global emissions in order to go into effect, is very likely.
The two countries chose the occasion of a G-20 meeting — a powwow among the heads of state of the world’s 20 largest economies — to announce their ratification, in order to focus attention on the issue of controlling climate change. UN Secretary General Ban Ki-Moon accepted the ratification papers with words of encouragement to other countries to do the same, so the climate agreement (COP21) can go into effect by year-end.
Although progress has been made in the direction of curtailing greenhouse gas emissions, atmospheric CO2 is now permanently above 400 parts per million, and there’s no telling what amount could be the atmosphere’s equivalent of the Chandrasekahr limit — the concentration beyond which large-scale changes in atmospheric circulation are inevitable.
Decoded Science has frequently pointed to the temperature of Venus, a planet with runaway greenhouse effect, as a warning: 500° C (over 900° F).
New Hurricane Forecasting Policy Gets First Test
Much of the damage caused by Superstorm Sandy can be attributed to an antiquated forecasting rule that required hurricane warnings to be discontinued as Sandy became extra-tropical. The meaningless distinction, for practical purposes, between types of storm — wind is wind, storm surge is storm surge, no matter the technical cause — meant that no warnings were issued for the New York City area and the storm took many by surprise.
Former Hurricane Hermine transitioned to a post-tropical storm — which means it now has characteristics of a mid-latitude winter storm — several days ago. Yet it continued to be a danger to citizens on the Atlantic coast. The National Hurricane Center has continued to post advisories as if the storm were still tropical.
Decoded Science applauds the change in policy.
Storms of either kind are cyclonic (in the northern hemisphere) systems. Tropical storms derive their energy from the heat stored in the ocean, while mid-latitude storms are fueled by the potential energy of adjacent warm and cold air masses. Energy is energy and, as we said, wind is wind. Hybrid storms are not uncommon. Hermine is a dangerous storm no matter how it is classified. Powerful winds and surf have raked the mid-Atlantic coast for the past four days; residents, boating interests, and beachgoers were properly warned.
Late News: Hurricane Hits Baja California
Hurricane Newton struck southern Baja California this morning as a category one hurricane.
It is forecast to retain hurricane strength as it crosses Baja today and reaches the mainland Mexico coast on Wednesday. The storm could still have tropical storm force winds as it reaches Arizona on Thursday.
The Feel Of Fall
The fall equinox is on September 22, when the sun will be exactly over the equator and heading for the southern hemisphere. In the northern hemisphere, the angle of the sun is decreasing daily; temperatures are falling over the US and Europe.
Meanwhile, the Atlantic Basin hurricane season peaks on September 10.
What signs of fall do you see in your neighborhood?