Year 2000-today

List of contents

 

 

 

2001-2003: Jakobshavn Isbræ in West Greenland retreats rapidly       

Frontal positions of calving Jakobshavn Isbræ since 1851, after reaching the maximum Little Ice Age position around 1850 (Bauer et al. 1968). Between 1893 and 2003 the glacier front retreated about 34 km. According to inuit legends, the embayment Tissarissoq used to be glacier-free in the past and was used as hunting area (Hammer 1883), most likely before before the Little Ice Age glacier advance (Weidick et al. 2004). Picture source: Google Earth.

 

The Disko Bay region in central West Greenland (c. 70oN) is characterised by large outlet glaciers from the Greenland Ice Sheet (the Indland Ice). The major glacier Jakobshavn Isbræ is situated in a major subglacial valley, which can be traced inland for about 100 km (Echelmeyer et al. 1991). The water depth in the fjord reaches 1500 m in its outer parts (Iken et al. 1993). 

Jakobshavn Isbræ is the main outlet glacier from the Greenland Ice Sheet, draining ice from about 6.5% of the total area of the ice sheet, and producing 30-45 km3 icebergs per year. This corresponds to more than 10% of the total output of icebergs from the Greenland Ice Sheet, and the Jakobshavn Isbræ is the most productive glacier in the northern hemisphere. The glacier flow velocity is also high, typically 20-22 meters per day. It is likely that the iceberg which sank Titanic in 1912 may have been produced by Jakobshavn Isbræ.

The first half of the 20th century was characterised by a 11 km frontal retreat of calving Jakobshavn Isbræ, following warming after the end of the Little Ice Age. During the latter half of the 20th century the glacier front was in an almost stable position, standing across a broad section of the fjord. Presumably, the quasi-stable glacier front position was influenced by the subglacial topography (Echelmeyer et al. 1991; Weidick 1992).

During the period 1850-1950 it has been estimated the the Jakobshavn Isbræ lost more than 200 m in ice thickness (Weidick 1992), gradually making is more easy for the glacier to float. Also between 1960 and 1980 the glacier thinning proceeded (Echelmeyer et al. 1991). Between 1993 and 1998 a slight thickening may have taken place (Abdalati et al. 2001), but from 1998 rapid thinning again dominated, spreading inland. The reduced ice thickness gradually made the glacier more prone to floating and thereby rapid calving, and around the year 2000 substantial changes of the calving front were therefore expected to take place (Weidick et al. 2004).

The expected rapid calving retreat took place from 2001 to 2003. In 2002 people living in Ilulissat observed unusually many icebergs in the icefjord, and observations carried out in 2003 further inland showed the floating glacier front to have retreated many kilometres (see picture above). At the same time, however, the position of the land-based glacier front of the ice sheet north and south of the floating glacier front has been stable. Thus, the spectacular calving retreat 2001-2003 should not be seen as a direct result of meteorological conditions during this short period, but instead reflects developments over a longer period. In addition, the depth and geometry of the fjord also influences on the retreat rate. Finally, the early 21st century air temperature in West Greenland is still clearly below what was recorded around 1940. Click here to see the entire temperature record from the capital at Nuuk, south of Jakobshavn.

Descriptions of the previous retreat of the glacier Jakobshavn Isbræ during the periods 1851-1893 and 1893-1942 can be found here and here, respectively.

Click here to jump back to the list of contents.

 

 

2002: New knowledge obtained on Kilimanjaro glaciers    

The stratovolcano Kilimanjaro (5895 m asl.) in northeastern Tanzania (left). The Furtwängler Glacier on the summit plateau of Kilimanjaro (right). The vertical ice cliffs are about 40 m high.

 

Kilimanjaro (5895 m asl.) is an inactive stratovolcano in northeastern Tanzania, near the border to Kenya. Kilimanjaro is also the tallest free-standing mountain in the world, rising 4,600 m from the surrounding plains. The first official climb of the highest summit was on 6 October 1889 by the German Hans Meyer, the Austrian Ludwig Purtscheller, guided by the Marangu army scout Yohanas Kinyala.

The glaciers on Kilimanjaro have attracted much recent interest, especially in relation to global temperature changes. The Furtwängler Glacier (see illustration above) is located near the summit, and is a remnant of a bigger icecap which once crowned the summit of Mount Kilimanjaro . This glacier is named after Walter Furtwängler, who along with Ziegfried Koenig, were the fourth to ascend to the summit of Kilimanjaro in 1912. Furtwängler Glacier has lost much of its previous volume since first visited by Meyer and Purtscheller in 1889. Between 1912 and the 2000, about 80 percent of the glacier ice on the mountain has disappeared.

A detailed analysis of six ice cores retrieved from the ice fields on the summit of Kilimanjaro shows that those glaciers began forming about 11,700 years ago (Thompson et al. 2002). The ice core records from the Furtwängler Glacier suggests conditions at the Summit of Kilimanjaro today are returning to those characteristic for the site 11,000 years ago.

For decades it has been known that solar radiation and sublimation, not air temperature, are the primary factors for loss of ice from tropical glaciers. In the tropics glaciers exist only at the highest elevations, and their size is controlled more by seasonal changes in precipitation than by air temperatures. Observations of the volume change of glaciers on Kilimanjaro suggest their total volume had already decreased by 66 percent from 1889 to 1953. 

The balance between energy inputs and energy outputs are important to understand 20th century glacier reduction at Kilimanjaro. The primary input of energy is short-wave solar radiation, while ice loss is primarily by way of sublimation, the transition of ice directly to water vapour. Because neither solar radiation and sublimation depends primarily on surface air temperatures, air temperature change does not have a big role in the loss of ice from tropical glaciers. That this also applies to glaciers on Kilimanjaro can be seen from the fact that the ice on Kilimanjaro forms high vertical walls (see illustration above) and finger-like features called penitents (see illustration below), the result of sublimation driven by direct radiation from the sun, rather than ablation caused by warm air.

 

Examples of ice and snow penitentes from tropical areas. The individual blades are between 1.5 and 2m in height, but may be as high as several meters. Because penitentes are formed by sublimation driven by direct solar radiation, their axis indicate the approximate position of the sun at noon at this latitude and time of the year. Snow penitentes was first described by Darwin (1839). The term penitente date back at least to the beginning of the Little Ice Age, referring to Los Penitentes, the flagellant orders in Spain and Italy.

A prolonged dry period may be responsible for the shrinking glaciers on Kilimanjaro. Kaser et al (2004) found that a marked drop in atmospheric moisture at the end of the 19th century and the ensuing drier climatic conditions are likely to represent the main driver for 20th century glacier retreat on Kilimanjaro. Independent surface observations of water levels from nearby Lake Victoria suggest that water levels have been declining since the end of the 19th century (Thompson et al. 2002), lending support to the notion that the present glacier retreat is caused by more dry conditions, and that the large extent of the glaciers observed by Meyer and Purtscheller in 1889 was the result of a more humid period in eastern Africa at that time, rather than to lower air temperatures.

The ice core from from the Furtwängler Glacier (Thompson et al. 2002) yield evidence of three catastrophic droughts in the tropics 8,300, 5,200 and 4,000 years ago. The ice core also suggest a much wetter environment near Kilimanjaro 9,500 years ago, contemporary with the existence of Megalake Chad. The ice core also showed a 500-year period beginning around 8,300 years ago when methane levels in the ice dropped rapidly, suggesting that several lakes of Africa were beginning to dry up. Usually, atmospheric methane levels are assumed to reflect, among other things, the extent of the tropical wetlands.

In addition, the ice core showed an abrupt depletion in oxygen-18 isotopes that may signal a second drought event occurring around 5,200 years ago (Thompson et al. 2002). This coincides with the period when anthropologists believe people in the region began to come together to form cities and social structures. Prior to this, the population of mainly hunters and gatherers had been more scattered. A third marker type in the ice cores is a visible dust layer dating back to about 4,000 years ago (Thompson et al. 2002). This is interpreted as marking a severe 300-year drought which struck the region. Historical records show that a massive drought hit the Egyptian empire at the time and threatened the rule of the Pharaohs. Until this time, people in Africa had been able to exist and thrive in areas that are now just barren Sahara Desert.

Click here to jump back to the list of contents.

 

 

2006: Winter storm Narve in Northern Norway and record high temperature in Svalbard    

Examples of weather related news from different part of Russia and Europe during the period 16-23 January 2006.

 

The severe January 2006 winter storm named 'Narve' created chaos in especially northern Norway, but also larger of Norway, Sweden and Finland were affected. In the press it was presented as an example of 'extreme weather'.

The wind over a period of several days from 15 January increased from southerly and southeasterly direction, developing into a strong storm, almost reaching hurricane-like conditions during 19 January. The storm was not associated with much precipitation in northern Norway, but with air temperatures down to -25oC, exposing people to serious wind chill and frostbites. Many buildings were damaged by the wind and by flying debris.

At the same time a new high temperature record of was reported for Svalbard (78oN), about 1000 km north of Norway.

Many powerlines in northern Norway came down, and large areas, including the cities of Tromsø and Kirkenes lost electricity and heating. In southern Norway the southeasterly wind resulted in an ongoing blizzard for orographic reasons, as the air masses were lifted across the highlands after flowing across the ice-free sea south of Norway, picking up additional moisture. Also in this part of Norway powerlines failed, not so much because of the wind, but because of excessive amounts of snow. The storm lead to major disturbances for both railways and air traffic. Several major highways were closed because of large snowdrifts, and schools had to be evacuated both in southern and northern Norway.

Narve lasted to 21 January, before slowly beginning to abate. Because of the duration and strength, the storm immediately earned itself a place on the official list of 'extreme weather in Norway', indicating the special status of this meteorological event.

 

Weather maps showing surface air pressure and surface air temperatures over Europe 12, 16, 18 and 21 January 2006. Solid lines indicate lines of equal air pressure (isobars) and the colours indicate the temperature in degrees C. Sub-zero air temperatures are shown with green and blue colours, while above-zero temperatures are shown by yellow and red colours. Over the period the high pressure area with low air temperatures are seen to extent across eastern Europe, concentrating thermal and pressure contrasts over northern Norway and Sweden. Source: Universität zu Köln, Institut für Geophysik und Meteorologie.

 

The meteorological background for this storm was a large east-west air pressure gradient across northern Norway, because of a low pressure area over the North Atlantic and a high pressure over Russia and Finland. Actually, the high pressure area was a westerly extension of the Siberian high pressure area, which increased in extension to cover parts of eastern Europe as well because of extreme cold in Siberia and Russia. 

The record high air temperatures recorded in Svalbard was caused by the southerly air flow across the warm waters of the North Atlantic Drift, warming up the air masses before reaching Svalbard. The strong southerly winds also pressed the southern limit of Arctic sea ice around Svalbard further north than usual.

By this, both the new air temperature record in Svalbard and the northerly position of the sea ice limit was a result of the extended position of the Siberian high pressure. Unfortunately, this greater meteorological perspective was never clearly communicated by the relevant meteorological institutions. Therefore, many people even today see both features as the result of global warming. In reality, they were both results of cold conditions in Russia and Siberia.

 

Maps showing the anomaly of surface air temperatures January 2006, compared to average conditions 1998-2006. Much of the northern hemisphere was colder than average, especially Alaska, Siberia, Russia and Europe. In contrast, USA and Canada experienced warmer than average conditions, as did an area extending from northeast Greenland across Svalbard to the Taymyr peninsula in northernmost Siberia. This warm regional anomaly is the result of persistent airflow from SW across the North Atlantic, along the western extension of the Siberian high pressure (see diagrams above). By this, this part of the Arctic experienced above average temperatures in January 2006, leading to the above mentioned temperature record in Svalbard. Temperature scale in degrees Celsius. Data source: NASA Goddard Institute for Space Studies (GISS).

 

Click here to jump back to the list of contents.

 

 

2007: The Met Office Hadley Centre forecasts climate until 2014    

News release 10 August 2007: The forecast for 2014...

Climate scientists at the Met Office Hadley Centre will unveil the first decadal climate prediction model in a paper published on 10 August 2007 in the journal Science. The paper includes the Met Office's prediction for annual global temperature to 2014.

Over the 10-year period as a whole, climate continues to warm and 2014 is likely to be 0.3 °C warmer than 2004. At least half of the years after 2009 are predicted to exceed the warmest year currently on record . These predictions are very relevant to businesses and policy-makers who will be able to respond to short-term climate change when making decisions today. The next decade is within many people's understanding and brings home the reality of a changing climate.

The new model incorporates the effects of sea surface temperatures as well as other factors such as man-made emissions of greenhouse gases, projected changes in the sun's output and the effects of previous volcanic eruptions — the first time internal and external variability have both been predicted.

Team leader, Dr Doug Smith said: "Occurrences of El Nino, for example, have a significant effect on shorter-term predictions. By including such internal variability, we have shown a substantial improvement in predictions of surface temperature." Dr Smith continues: "Observed relative cooling in the Southern Ocean and tropical Pacific over the last couple of years was correctly predicted by the new system, giving us greater confidence in the model’s performance".

Click here to jump back to the list of contents.

 

2007: Scientists find evidence for subsea volcanic blast of CO2    

Location of Gakkel Ridge in the Arctic Ocean (yellow dot; left). Fine-grained volcanic debris blanketing the seafloor on the Gakkel Ridge. Grains like these are usually ejected by explosive eruptions and eventually settles through the water onto the seafloor (centre). Glassy, granular fragments of volcanic debris, providing evidence that volcanoes on the Arctic Ocean seafloor had erupted violently (right). Picture source: Google Earth and Carlowicz (2008).

 

Operating from the Swedish icebreaker Oden, a research team led by Woods Hole Oceanographic Institution in 2007 uncovered evidence of explosive volcanic eruptions on the Arctic Ocean seafloor almost 3.8 km deep. Usually, scientists would not expect volcanoes submerged under such intense water pressure to be capable of such violent eruptions. Researchers found jagged, glassy fragments of rock (pyroclastic deposits) spread out over a 10 km2 area around a series of small volcanic craters on the Gakkel Ridge, which is a little known extension of the mid-Atlantic ridge into the Arctic Ocean (Carlowicz 2008).

“These are the first pyroclastic deposits we've ever found in such deep water, at oppressive pressures that should inhibit the formation of steam, and many people thought this was not possible,” said Rob Reves-Sohn, chief scientist of an expedition to the Gakkel Ridge in July 2007. “This means that a tremendous blast of carbon dioxide was released into the water column during the explosive eruption.” Although only little is known about the deeper parts of the Arctic Ocean, the bottom water in this part of the Arctic Ocean is not expected to mix much with surface waters (Carlowicz 2008). The research findings were published in the journal Nature June 26, 2008.

Click here to read more about volcanoes.

Click here to jump back to the list of contents.

 

2008: Coastal erosion prompts Inuits in Alaska to sue oil and gas companies    

The location of the settlement Kivalina (ca. 68N, 165W) in northwestern Alaska. Kivalina is located on the northeastern shore of the Bering Strait. Easternmost Siberia is seen to the left. The picture measures about 2500 km from left to right. Source: Google Earth.

 

Inuits living in the coastal settlement Kivalina in northwestern Alaska (see location map above) are suing 24 oil and gas companies (February 27, 2008), claiming that sea ice melt caused by global warming poses an imminent threat to the Inupiat Eskimos who live there. Kivalina is located at the coast 70 miles north of the Arctic Circle, and have about 390 inhabitants. The complaint says that because of massive sea ice melting, the village is losing its traditional protection from weather and the village must relocate.

 

Arial photo of Kivalina, showing the partly ice covered Beiring Strait to the left, and land with rivers and lakes to the right. Kivalina is seen to be located on the coastal barrier island, separated from the mainland by a lagoon. The picture measures about 10 km from left to right. North is up. Source: Google Earth.

 

From a geomorphological point of view, the setting of Kivalina is interesting. The press release say that Kivalina is located on the tip of a barrier reef. This is not the case. The picture above shows the settlement to be located on a coastal barrier island (or shoal), caused by wave action, and thus demonstrating the occurrence of one or several previous periods with extensive open water conditions in the area, extensive enough to generate big waves. If not so, there would have been no barrier island to establish the settlement on. Thus, the present conditions with relatively little sea ice has most likely occurred one or several times before. Actually, in August 1728 Vitua Bering came close to Kivalina, sailing in open water. 

The barrier island on which Kivalina is located must be a relatively new landscape feature, geologically speaking. It is adjusted to the present relative sea level (relative to the land), which in this area probably was reached about 3000-4000 years ago. During this time interval the barrier island have been established by storms during previous open water situations.

Coastal barriers are notorious dynamic landforms, changing form, location and surface relief along with changes in wave activity, wind direction and -strength, and the supply of new sediments (usually sand) by rivers from the hinterland. In periods with high precipitation and high summer river discharge and resulting high sediment transport by rivers, coastal barrier islands tend to aggrade, while the opposite (erosion) dominates in periods with little supply of sediment by nearby rivers. Therefore, not only variations in sea ice, but also a number of other climatic and geomorphological factors control the fate of such delicate coastal features. Usually, coastal barrier islands are considered problematic locations for buildings, roads and other fixed installations. Especially locations near outlets from rivers or lagoons behind are exposed to rapid changes in the coastal outline.

In the Arctic mosquitoes represent a major nuisance, especially in July. Presumably the location for Kivalina was chosen to avoid mosquitoes from the many lakes in the hinterland, and to be close to the open sea during the open water period (summer). The number and outline of the numerous lakes in the hinterland signal the existence of permafrost in the area. Barrier islands tend to orient themselves perpendicular to the dominant wind direction during the open water period (summer). In the present case the prevailing summer wind direction apparently is from southwest, helping to keep the mosquitoes at bay in the hinterland, away from Kivalina.

Click here to jump back to the list of contents.

 

 

 

2008: Half the years between 2009 and 2014 forecasted as being warmer than 1998  

April 29, 2008, the fall in global temperatures led to a news release from the UK Met Office with the headline 'Is global warming all over?'

In the news release the present cooling is presented as an example of interannual variability, due to a number of natural factors, the single most important being the El Niño-Southern Oscillation or ENSO. The global climate is currently (April 2008) being influenced by the cold phase of this oscillation, known as La Niña. It is also stated that ten-year forecasts produced by the Met Office Hadley Centre captures this levelling of global temperatures in the middle of the decade, and that effectively La Niña has been masking the underlying trend in rising temperatures.  

Finally, it is stated that these same forecasts also predict continued and increased warming into the next decade, with half the years between 2009 and 2014 being warmer than the current warmest on record, 1998.

Click here to jump back to the list of contents.

 

 

2008: Global solar wind plasma output at 50-yr low  

NASA News Release 08-241 states the following about recent solar activity and potential consequences: 

Ulysses Reveals Global Solar Wind Plasma Output At 50-Year Low

WASHINGTON -- Data from the Ulysses spacecraft, a joint NASA-European Space Agency mission, show the sun has reduced its output of solar wind to the lowest levels since accurate readings became available. The sun's current state could reduce the natural shielding that envelops our solar system.

"The sun's million mile-per-hour solar wind inflates a protective bubble, or heliosphere, around the solar system. It influences how things work here on Earth and even out at the boundary of our solar system where it meets the galaxy," said Dave McComas, Ulysses' solar wind instrument principal investigator and senior executive director at the Southwest Research Institute in San Antonio. "Ulysses data indicate the solar wind's global pressure is the lowest we have seen since the beginning of the space age."

The sun's solar wind plasma is a stream of charged particles ejected from the sun's upper atmosphere. The solar wind interacts with every planet in our solar system. It also defines the border between our solar system and interstellar space. This border, called the heliopause, surrounds our solar system where the solar wind's strength is no longer great enough to push back the wind of other stars. The region around the heliopause also acts as a shield for our solar system, warding off a significant portion of the cosmic rays outside the galaxy.

"Galactic cosmic rays carry with them radiation from other parts of our galaxy," said Ed Smith, NASA's Ulysses project scientist at the Jet Propulsion Laboratory in Pasadena, Calif. "With the solar wind at an all-time low, there is an excellent chance the heliosphere will diminish in size and strength. If that occurs, more galactic cosmic rays will make it into the inner part of our solar system."

Galactic cosmic rays are of great interest to NASA. Cosmic rays are linked to engineering decisions for unmanned interplanetary spacecraft and exposure limits for astronauts traveling beyond low-Earth orbit.

In 2007, Ulysses made its third rapid scan of the solar wind and magnetic field from the sun's south to north pole. When the results were compared with observations from the previous solar cycle, the strength of the solar wind pressure and the magnetic field embedded in the solar wind were found to have decreased by 20 percent. The field strength near the spacecraft has decreased by 36 percent. "The sun cycles between periods of great activity and lesser activity," Smith said. "Right now, we are in a period of minimal activity that has stretched on longer than anyone anticipated."

Ulysses was the first mission to survey the space environment over the sun's poles. Data Ulysses has returned have forever changed the way scientists view our star and its effects. The venerable spacecraft has lasted more than 18 years, or almost four times its expected mission lifetime. The Ulysses solar wind findings were published in a recent edition of Geophysical Research Letters.

The Ulysses spacecraft was carried into Earth orbit aboard space shuttle Discovery on Oct. 6, 1990. From Earth orbit it was propelled toward Jupiter, passing the planet on Feb. 8, 1992. Jupiter's immense gravity bent the spacecraft's flight path downward and away from the plane of the planets' orbits. This placed Ulysses into a final orbit around the sun that would take it over its north and south poles.

The Ulysses spacecraft was provided by ESA, having been built by Astrium GmbH (formerly Dornier Systems) of Friedrichshafen, Germany. NASA provided the launch vehicle and the upper stage boosters. The U.S. Department of Energy supplied a radioisotope thermoelectric generator to power the spacecraft. Science instruments were provided by U.S. and European investigators. The spacecraft is operated from JPL by a joint NASA-ESA team.

More information about the Ulysses mission is available on the Web at:   http://ulysses.jpl.nasa.gov

Click here, here, here and here for a few additional relevant links.

Click here to see the most recent estimates of the global temperature (monthly resolution).  

Click here to jump back to the list of contents.

 

2009: The the quietest sun seen in almost a century  

The sunspot cycle from 1995 to the present (March 2009; NASA; left). Total solar irradiance calculated as the brightness summed across all wavelengths (NASA; right).

 

NASA Science News for April 1, 2009: The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower. 2008 was a bear. There were no sunspots observed on 266 of the year's 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008. Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year's 90 days (87%).

It adds up to one inescapable conclusion: "We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of the Goddard Space Flight Center. "This is the quietest sun we've seen in almost a century," agrees sunspot expert David Hathaway of the Marshall Space Flight Center.

Click here, here, here and here for a few additional relevant links. Click here to see the most recent estimates of the global temperature (monthly resolution).  

Click here to jump back to the list of contents.