Earth Wise

A look at our changing environment.

You are here: Home / Archives for september

september

Record low Antarctic sea ice

By Leave a Comment

Antarctica’s winter came to a close in September and during that month, the continent reaches its maximum amount of sea ice that grows during the darkest and coldest months.  This year, that maximum occurred on September 10th and turned out to be the lowest on record.

The sea ice around Antarctica reached a maximum extent of 6.5 million square miles according to NASA researchers.  That was nearly 400,000 square miles below the previous record low set in 1986. 

There are several possible causes for the meager growth of Antarctic sea ice this year.  It may be a combination of several factors including El Niño, wind patterns, and warming ocean temperatures.  Recent research indicates that ocean heat is most likely playing an important role in slowing ice growth in the cold season and enhancing ice melting in the warm season.

The record-low ice extent so far this year is a continuation of a downward trend in Antarctic sea ice that has gone on since the ice reached a record high in 2014.  Prior to that year, the ice surrounding the southern continent was actually increasing slightly by about 1% every decade.

Meanwhile, Arctic sea ice reached its minimum extent in September and it was the sixth-lowest level in the satellite record.  Scientists track the seasonal and annual fluctuations of polar sea ice because they shape polar ecosystems and play a significant role in global climate.  Sea ice melting at both poles reinforces global warming because bright sea ice reflects most of the Sun’s energy back to space while open ocean water absorbs 90% of it.

**********

Web Links

Antarctic Sea Ice Sees Record Low Growth  

Photo, posted June 30, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mississippi River Running Dry | Earth Wise

By Leave a Comment

Water levels in the lower Mississippi River are running very low.  During September, the readings in Memphis, Tennessee were within inches of the all-time low.  The situation is causing real problems for the grain export industry.

The water levels of the lower Mississippi are determined by the amount of rainfall in the upper Midwest.  At the point where the Ohio and Mississippi Rivers come together, about 90% of the water headed for the lower Mississippi has been accumulated.

Almost 400 miles of the Mississippi have experienced water levels at or below critical levels for shipping.  During September, parts of the Mississippi have been closed to ship traffic more than 20 times.  At least 36 vessels were reported to have run aground.

The low water levels on the river have caused shippers of soybean and corn exports to lighten their loads to keep the vessels from running aground.  They have also reduced how many barges they pull at once in order to be able to navigate shipping channels that have narrowed because of the reduced water levels.

Fall is the busiest grain export season for the region.  About 60% of grain exports from the Midwest leave the U.S. through terminals on the Gulf Coast.  The low levels of the Mississippi River threaten gridlock for this vital industry.  It has caused freight costs to be the highest since historic river lows last year caused U.S. grain to be less competitive globally.

Unfortunately, October is not normally a strong precipitation month, but the hope is that the El Niño now underway may lead to increased precipitation in the Southern U.S.

**********

Web Links

Mississippi River Nears Historic Lows, Putting Grain Exports at Risk

Photo, posted March 8, 2023, courtesy of Errol Sandler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Hottest September | Earth Wise

By Leave a Comment

Here’s a news item that is like many other recent news items:  September 2020 was the hottest September since 1880, according to the National Oceanic and Atmospheric Administration.   The warm September is a part of a year that so far is poised to be at least the second hottest year in the 141-year climate record.

The ten warmest Septembers on record have all occurred since 2005, and the seven warmest Septembers have occurred in the past seven years.

So far, the year-to-date average global temperature has been the second warmest on record, being just 0.07 degrees Fahrenheit lower than the record year-to-date temperature set in 2016.  Expectations are that 2020 will end up somewhere among the three warmest years on record for the globe.

September was warm in many places around the world.  California and Oregon had their warmest September ever.  Europe had its warmest September on record, Asia had its second warmest September on record as did Australia and South America. 

So far, it has been the hottest year-to-date on record in Europe, Asia, and the Gulf of Mexico.  No land or ocean areas anywhere had record-cold year-to-date temperatures. 

Global temperatures represent an average over the entire surface of the planet.  The fact that the global temperature is now nearly one Celsius degree above the 20th century average means that a vast amount of heat has been added in order to warm all the oceans, atmosphere, and land by that much.  So, every uptick in global temperature is a big deal.

Meanwhile, the average Arctic sea ice coverage for September was the second smallest on record.  The 14 smallest minimum annual sea ice extents have all occurred in the past 14 years.

**********

Web Links

Earth just had its hottest September on record

Photo, posted September 2, 2020, courtesy of Tim Vrtiska via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)