southern hemisphere

Missing Antarctic Sea Ice | Earth Wise

August 30, 2023 By EarthWise Leave a Comment

It is summer here in the United States, but it is winter in Antarctica. Antarctic sea ice is water that forms and melts entirely in the ocean and it has a pattern of growth and reduction that has been monitored by satellites for the past 44 years. The area of sea ice that surrounds the continent of Antarctica is known as the sea ice ‘extent’ and it had been quite stable for much of those years.

In 2016, the sea ice extent began to decline. Since then, there have been several record summer lows with both the summers of 2021/22 and 2022/23 setting new minimum records.

This August, the deviation from all previous records intensified. This winter’s sea ice extent is over 900,000 square miles below the long-term average, an area about the size of Greenland or, for example, Texas and Alaska combined.

Climate models have long predicted that Antarctic sea ice would reduce as a result of global warming but the current change to sea-ice extent is so dramatic that it is difficult to explain. Sea ice extent is affected by multiple factors including the El Niño Southern Oscillation, the strength of the southern hemisphere jet stream, and regional low-pressure systems. The warming climate is certainly the overall force that is changing Antarctic sea ice extent over time.

Antarctic sea ice extent is important because it covers a vast area of the dark Southern Sea with a bright white surface that reflects the sun’s energy back into space, helping to reduce temperatures at the pole and protecting glaciers and polar ice sheets.

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The mystery of the missing Antarctic sea ice

Photo, posted November 7, 2016, courtesy of Rob Oo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Low Antarctic Sea Ice | Earth Wise

March 2, 2023 By EarthWise Leave a Comment

Recent satellite observations of the sea ice in the Antarctic found the lowest level of ice cover ever seen in the forty years that these observations have been made. As of February 8th, there were only 849,000 square miles of the Southern Ocean covered with ice. The previous record low was measured last February 24th when the total coverage was 876,000 square miles. Ice melting was likely to continue as the month went on.

This past January had already set a new record for that month’s mean extent of ice coverage at 1.24 million square miles. This rapid decline in sea ice has been going on for the past six years and is very unusual. Average Antarctic ice cover hardly changed at all during the previous thirty-five years.

Antarctic sea ice generally reaches its maximum extent in September or October and its minimum extent in February. At its maximum, the sea ice cover in the Antarctic is generally between 6.9 and 7.7 million square miles. On the other hand, there are some places where the sea ice melts completely during the Southern Hemisphere summer. Sea ice varies much more in the Antarctic than in the Arctic where the ice is much thicker.

Climate warming at the poles is much higher than at lower latitudes. Nonetheless, it is not yet clear whether what we are seeing is the beginning of the end of summer sea ice in the Antarctic, or whether this is just a new phase characterized by low but still stable sea ice cover in the summer.

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Record low sea ice cover in the Antarctic

Photo, posted January 24, 2012, courtesy of Rob Oo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The All-Time Hottest Day | Earth Wise

February 14, 2022 By EarthWise Leave a Comment

Last year saw record high temperatures in many places around the world and this year started out with more of the same. In mid-January, Onslow, a small town in Western Australia, measured a high temperature of 123.3 degrees, tying the all-time highest temperature ever recorded anywhere in the Southern Hemisphere. The previous reading was also made in Australia back in 1960.

The new temperature record was set just as climate institutions around the world were announcing that the past seven years have been the highest in recorded history.

The list of temperature records set in 2020 and 2021 is a long one. 2020 was the hottest year in recorded history. July 2021 was the hottest month ever recorded. The hottest official temperature ever recorded anywhere in the world was 129.9 degrees, occurring in Death Valley, California on both August 16, 2020, and July 9, 2021.

The hottest temperature ever recorded in the Arctic was 100.4 degrees on June 20, 2020 in Verkhoyansk in Russia’s Sakha Republic. (Amazingly, that small town also holds the record for the coldest temperature ever recorded in Asia at -90 degrees). 2021 saw an all-time high temperature recorded in Europe, in Syracuse, Sicily, on August 11 at 119.8 degrees.

Overall, 400 documented weather stations in communities or outposts worldwide established all-time high temperatures in 2021 alone. The climate we have lived through over the past decades is changing and these changes will have consequences to our way of life.

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Australia hits 123 degrees, tying hottest temperature on record in Southern Hemisphere

Photo, posted January 21, 2013, courtesy of A. Dombrowski via Flickr.

In ogni caso, un proverbio russo comune Informazioni: “Se curi un raffreddore, passa in sette giorni, e se non lo curi, in una settimana”, non è applicabile alla realtà spagnola.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Hurricanes In The Northeast | Earth Wise

February 9, 2022 By EarthWise Leave a Comment

According to a new study led by Yale University, more hurricanes are likely to hit Connecticut and the northeastern U.S. as global warming continues to increase temperatures in the region.

Hurricane Henri made landfall in August as a tropical storm on the Connecticut/Rhode Island border. In September 2020, subtropical storm Alpha made landfall in Portugal, the first subtropical or tropical cyclone ever observed to make landfall in the mainland of that country.

Tropical cyclones, hurricanes, and typhoons are typically intense and destructive in the lower latitudes.

The study concludes that violent storms could migrate northward in our hemisphere and southward in the southern hemisphere as a result of warming caused by greenhouse gas emissions.

The research predicts that tropical cyclones will likely occur over a wider range of latitudes than has been the case on Earth for the last 3 million years.

In Connecticut, Hurricane Henri was not the only tropical storm to affect the region in 2021. The remnants of Hurricane Ida brought damaging winds and torrential rain that felled trees and flooded streets and basements.

The northern expansion of such violent storms is going on as water levels in the Atlantic Ocean and Long Island Sound keep rising. Because of melting glaciers thousands of miles away, water levels in Long Island Sound could rise by as much as 20 inches by 2050, enough to submerge parts of Groton’s shore and cause regular flooding in roads and neighborhoods.

Future hurricane prediction is an inexact science, but the ongoing trends do not bode well for the region.

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More hurricanes likely to slam Connecticut and region due to climate change, says study

Photo, posted October 29, 2012, courtesy of Rachel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Side Effects Of Geoengineering | Earth Wise

July 20, 2020 By EarthWise Leave a Comment

As the world struggles to reduce the greenhouse gas emissions that are warming the global climate, some researchers are exploring proposals to deliberately engineer climate changes to counteract the warming trend. One of the most widely discussed approaches is to shade the Earth from a portion of the sun’s heat by injecting the stratosphere with reflective aerosol particles. Proponents of this idea point out that volcanoes do essentially the same thing, although generally for only a limited amount of time. Particularly large eruptions, such as the Krakatowa eruption of 1883, wreaked havoc with weather around the world for an entire year.

Schemes to launch reflective aerosols – using planes, balloons, and even blimps – appear to be quite feasible from the standpoint of physically accomplishing them. But this says nothing about the political, ethical, and societal issues involved. The point is that such an approach could indeed lower global temperatures and thereby potentially offset the warming effects of greenhouse gases.

A study by scientists at MIT looked at what other effects such a solar geoengineering project might have on the climate. Their modeling concluded that it would significantly change storm tracks in the middle and high latitudes. These tracks give rise to cyclones, hurricanes, and many more ordinary weather phenomena.

According to the study, the northern hemisphere would have weakened storm tracks, leading to less powerful winter storms, but also stagnant conditions in summer and less wind to clear away air pollution. In the southern hemisphere, there would be more powerful storm tracks.

Aside from turning the world’s weather patterns inside out, solar geoengineering would do nothing to address the serious issue of ocean acidification caused by increasing carbon dioxide levels.

As many have pointed out, playing the geoengineering game would have many unintended consequences.

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Study: Reflecting sunlight to cool the planet will cause other global changes

Photo courtesy of MIT.

Earth Wise is a production of WAMC Northeast Public Radio.

Antarctica’s Hot Summer | Earth Wise

May 1, 2020 By EarthWise Leave a Comment

The Southern Hemisphere’s recent summer brought drought, heatwaves and bush-fires that ravaged Australia. At the same time, Antarctica experienced a summer of extreme weather.

In East Antarctica, the Casey research station in the Australian Antarctic Territory had its first heatwave event, recording extreme maximum and minimum temperatures over three consecutive days in January. Record high temperatures were also reported at bases on the Antarctic Peninsula.

The Casey station recorded a record high maximum temperature of 49 degrees Fahrenheit and a record overnight low of 36 degrees. In February, Brazilian scientists reported a high temperature of 69 degrees at Marambio, an all-time record for Antarctica.

Ecologists say that the hot summer would most likely lead to long-term disruption of local populations, communities, and the broader ecosystem. That disruption could be both positive and negative.

Most life in Antarctica exists in small ice-free oases and depends on melting snow and ice for a water supply. Melt water from the warming temperatures will lead to increased growth and reproduction of mosses, lichens, microbes and invertebrates.

However, excessive flooding can dislodge plants and alter the composition of communities of invertebrates and microbial mats. If the ice completely melts early in the season, then ecosystems will suffer drought for the rest of the season.

Extreme events often have impacts for years after the event. There will be long-term studies of the areas affected by the recent Antarctic heat wave. Such extreme events associated with global climate change are predicted to increase in frequency and impact, and even the most remote areas of the planet are not immune to them.

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Antarctica’s summer of extreme heat

Photo, posted January 30, 2014, courtesy of Andreas Kambanis via Flickr

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Temperature Variations

June 20, 2018 By EarthWise Leave a Comment

It’s no surprise that not everyone on the planet is equally responsible for the effects of climate change. For instance, the Northern Hemisphere, which is home to 13 of the 15 largest countries by GDP, emits far more greenhouse gases than the Southern Hemisphere does. But the whole planet heats up as a result.