Sentences with phrase «ice concentration over»

The positive temperature trends over the WAIS are spatially adjacent to the negative trends in sea ice concentration over the Amundsen and Bellingshausen Seas.

A look at Arctic sea ice concentration over the last 100 years (through 2013) using the latest NSIDC gridded 1850 - reconstruction from Walsh et al. [2016].

The important news is that in five summers the sea ice concentration over the Arctic has not recovered from its precipitous decline in 2007.

The BRT then manufactured an untested sea - ice threshold based solely on circumstantial evidence to assert whelping and nursing required sea ice concentrations over 25 %.

Not exact matches

Growth rates for concentrations of carbon dioxide have been faster in the past 10 years than over any 10 - year period since continuous atmospheric monitoring began in the 1950s, with concentrations now roughly 35 percent above preindustrial levels (which can be determined from air bubbles trapped in ice cores).

Curiously, the decline in atmospheric oxygen over the past 800,000 years was not accompanied by any significant increase in the average amount of carbon dioxide in the atmosphere, though carbon dioxide concentrations do vary over individual ice age cycles.

A shift of 100 ppm in CO2 concentrations meant the difference between flowers blooming in the Arctic and ice a mile deep over Chicago.

The Mars Express observations hint at greater methane concentrations over areas containing subsurface water ice.

Ice cores provide evidence for variation in greenhouse gas concentrations over the past 800,000 years.

CO2 will also diffuse through the ice at a set rate and the effect over time will be that the CO2 concentration will be a function of the vapor pressure of the CO2 in the trapped air, and the rate of diffusion of the CO2 through the ice.

Seasonal to centennial - scale variability of microparticle concentration and size distribution in the WAIS Divide ice core over the past 2.4 ka.

Ice - core Records of Atmospheric Halogen Concentrations over Western Antarctica - Past and Present.

The AMO is likely to be a driver of multi-decadal variations in Sahel droughts, precipitation in the Caribbean, summer climate of both North America and Europe, sea ice concentration in the Greenland Sea and sea level pressure over the southern USA, the North Atlantic and southern Europe (e.g., Venegas and Mysak, 2000; Goldenberg et al., 2001; Sutton and Hodson, 2005; Trenberth and Shea, 2006).

However, atmospheric CO2 content plays an important internal feedback role.Orbital - scale variability in CO2 concentrations over the last several hundred thousand years covaries (Figure 5.3) with variability in proxy records including reconstructions of global ice volume (Lisiecki and Raymo, 2005), climatic conditions in central Asia (Prokopenko et al., 2006), tropical (Herbert et al., 2010) and Southern Ocean SST (Pahnke et al., 2003; Lang and Wolff, 2011), Antarctic temperature (Parrenin et al., 2013), deep - ocean temperature (Elder eld et al., 2010), biogeochemical conditions in the Northet al., 2008).

Alarmed at the pace of change to our Earth caused by human - induced climate change, including accelerating melting and loss of ice from Greenland, the Himalayas and Antarctica, acidification of the world's oceans due to rising CO2 concentrations, increasingly intense tropical cyclones, more damaging and intense drought and floods, including glacial lakes outburst loods, in many regions and higher levels of sea - level rise than estimated just a few years ago, risks changing the face of the planet and threatening coastal cities, low lying areas, mountainous regions and vulnerable countries the world over,

A statistical forecast using a regression based approach with fall surface air temperature anomalies over the region as the main predictor was submitted by Tivy (Figure 4) for ice concentration anomalies in September.

With global GHG emissions and concentrations continuing to increase; with climate change intensifying changes in ecosystems, ice sheet deterioration, and sea level rise; and with fossil fuels providing more than 80 % of the world's energy, the likelihood seems low that cooperative actions will prevent increasingly disruptive climate change over the next several decades.

please read Z. Jaworowski's (with Segalstad and Ono) many papers on this subject of trapped gases in glaciers, where he discusses the over 20 mechanical and chemical processes that make accurate measurements impossible; even in shallow cores above the point where co2 is supposedly permanently trap in ice cavities in the firn, co2 concentrations are already 20 - 40 % lower than those measured in air at mauna loa.

July 19: Dr. Stephen Schneider passed away unexpectedly in London • July 17: The Polar Science Center observes anomalous drop in Arctic ice volume • July 16: The National Academy of Sciences released a summary report on climate stabilization targets pertaining to emissions, concentrations, and impacts over decades to millennia.

Figure 1: Carbon dioxide concentrations in the atmosphere over both the last 1000 years and the preceding 400,000 years as measured in ice cores

«We build on this insight to demonstrate directly from ice - core data that, over glacial — interglacial timescales, climate dynamics are largely driven by internal Earth system mechanisms, including a marked positive feedback effect from temperature variability on greenhouse - gas concentrations.»

The vulnerable nations declared that they are, «Alarmed at the pace of change to our Earth caused by human - induced climate change, including accelerating melting and loss of ice from Greenland, the Himalayas and Antarctica, acidification of the world's oceans due to rising CO2 concentrations, increasingly intense tropical cyclones, more damaging and intense drought and floods, including Glacial Lakes Outburst Floods, in many regions and higher levels of sea - level rise than estimated just a few years ago, risks changing the face of the planet and threatening coastal cities, low lying areas, mountainous regions and vulnerable countries the world over...»

Over land the northern hemisphere; Globsnow snow - water - equivalent SWE product and over sea the EUMETSAT OSI - SAF sea - ice concentration prodOver land the northern hemisphere; Globsnow snow - water - equivalent SWE product and over sea the EUMETSAT OSI - SAF sea - ice concentration prodover sea the EUMETSAT OSI - SAF sea - ice concentration product.

Over land the northern hemisphere Globsnow snow - water - equivalent SWE product and over sea the OSI - SAF sea - ice concentration prodOver land the northern hemisphere Globsnow snow - water - equivalent SWE product and over sea the OSI - SAF sea - ice concentration prodover sea the OSI - SAF sea - ice concentration product.

A temporally more consistent time series of sea ice concentrations is provided, offering improved accuracy over the ice concentration maps created from the original Bootstrap algorithm.

Extent here is defined as the total area of ice with concentration (over an area of at least 100 square kilometers) greater than 15 %.

All of this will be over by 2015, when the records of 2010 and 1998 will have been obliterated by increased solar activity, ENSO and decreased albedo as we go into virtually ice free arctic summers, oh and increased GHG concentrations of course.

The AMO is likely to be a driver of multi-decadal variations in Sahel droughts, precipitation in the Caribbean, summer climate of both North America and Europe, sea ice concentration in the Greenland Sea and sea level pressure over the southern USA, the North Atlantic and southern Europe (e.g., Venegas and Mysak, 2000; Goldenberg et al., 2001; Sutton and Hodson, 2005; Trenberth and Shea, 2006).

6 Ice age — time in the past when continental glaciers covered large parts of Earth's surface Global warming — a gradual increase in the temperature of Earth's atmosphere Greenhouse gas — Gases in the atmosphere, such as carbon dioxide, that trap solar energy Ozone hole — a large area of reduced ozone concentration in the stratosphere, found over Antarctica Chlorofluorocarbon — chlorine compounds that are the main cause of ozone depletion KEY TERMS

This can be inferred from ice core measurements, which show a near constant atmospheric concentration of CO2 over the last several thousand years prior to the Industrial Era.

In contrast, SLP has been higher over the Kara sector, which may have contributed to the large current negative anomalies in sea ice concentration in that region of the Arctic.

Once the ice barrier at the top of the strait gives way, ice from the Arctic Ocean can spill over into this region, affecting navigation, but also providing a mechanism to reduce ice concentrations in an area of very thick ice in the high Arctic.

Top row (a — c): Regressions of the leading detrended Z850 PC timeseries with anomalies in continental Antarctic temperature from M10 (colors on Antarctic land), sea ice concentration (colors over ocean; (note the sea ice colorscale is reversed with respect to the temperature colorscale), and geopotential height (contours).

The colorscale over the ocean region indicates the mean sea ice concentration for SON and the vectors indicate the SON mean 10 m wind vectors.

a 30 - year (1979 — 2008) trends in temperature from M10 (colors on Antarctic land), sea ice concentration (colors over ocean; note the sea ice colorscale is reversed with respect to the temperature colorscale), and Z850 (contours).

The concentration of CO2 varied between about 200 and 280 ppmv over the last several ice age cycles, and caused approximately 2 Wm 2 variations in surface longwave radiation forcing [e.g., Ramaswamy et al., 2001].

NASA even states that when they lowered the CO2 concentration again, their model reproduced a nice ice cap over the Arctic Ocean, which implies Arctic ice loss is not irreversible — although that conclusion is highly theoretical:

It is widely recognized that modern Arctic region sea ice concentrations are considerably more advanced today than they were a few thousand years ago, with most studied regions showing the increase in sea ice extent occurring «over the last centuries».

Even though it causes only a small reduction in concentration - the input to the Slater model - «this trigger accelerates ice melt through the enhanced solar heat input over the open water fraction.»

Measurements of air in ice cores show that for the past 800,000 years up until the 20th century, the atmospheric CO2 concentration stayed within the range 170 to 300 parts per million (ppm), making the recent rapid rise to nearly 400 ppm over 200 years particularly remarkable [figure 3].

Scientific confidence of the occurrence of climate change include, for example, that over at least the last 50 years there have been increases in the atmospheric concentration of CO2; increased nitrogen and soot (black carbon) deposition; changes in the surface heat and moisture fluxes over land; increases in lower tropospheric and upper ocean temperatures and ocean heat content; the elevation of sea level; and a large decrease in summer Arctic sea ice coverage and a modest increase in Antarctic sea ice coverage.

Consider, for example, that Lowe, et al. [in Avoiding Dangerous Climate Change, H.J. Schellnhuber et al. (eds), Cambridge University Press, Cambridge, 2006, p. 32 - 33], based on a «pessimistic, but plausible, scenario in which atmospheric carbon dioxide concentrations were stabilised at four times pre-industrial levels,» estimated that a collapse of the Greenland Ice Sheet would over the next 1,000 years raise sea level by 2.3 meters (with a peak rate of 0.5 mm / yr).

Because all 2013 Intergovernmental Panel on Climate Change scenarios — except Representative Concentration Pathway 2.6 (RCP2.6), which leads to the total radiative forcing of greenhouse gases of 2.6 W m − 2 in 2100 — imply that cumulative carbon emission will exceed 1,000 Gt in the twenty - first century, our results suggest that anthropogenic interference will make the initiation of the next ice age impossible over a time period comparable to the duration of previous glacial cycles.»

The fact that the earth appears to have gone through huge changes in atmospheric CO2 concentration over geologic eras, while the estimated temps went from 12degC to 22 deg C regardless of «Snowball Earth» or «Cretaceous Hot House» with both hot and cold periods occurring during both high and low CO2 regimes and both with and without ice caps argues very strongly that we do not understand the climate mechanism at all.

RealClimate is wonderful, and an excellent source of reliable information.As I've said before, methane is an extremely dangerous component to global warming.Comment # 20 is correct.There is a sharp melting point to frozen methane.A huge increase in the release of methane could happen within the next 50 years.At what point in the Earth's temperature rise and the rise of co2 would a huge methane melt occur?No one has answered that definitive issue.If I ask you all at what point would huge amounts of extra methane start melting, i.e at what temperature rise of the ocean near the Artic methane ice deposits would the methane melt, or at what point in the rise of co2 concentrations in the atmosphere would the methane melt, I believe that no one could currently tell me the actual answer as to where the sharp melting point exists.Of course, once that tipping point has been reached, and billions of tons of methane outgass from what had been locked stores of methane, locked away for an eternity, it is exactly the same as the burning of stored fossil fuels which have been stored for an eternity as well.And even though methane does not have as long a life as co2, while it is around in the air it can cause other tipping points, i.e. permafrost melting, to arrive much sooner.I will reiterate what I've said before on this and other sites.Methane is a hugely underreported, underestimated risk.How about RealClimate attempts to model exactly what would happen to other tipping points, such as the melting permafrost, if indeed a huge increase in the melting of the methal hydrate ice WERE to occur within the next 50 years.My amateur guess is that the huge, albeit temporary, increase in methane over even three or four decades might push other relevent tipping points to arrive much, much, sooner than they normally would, thereby vastly incresing negative feedback mechanisms.We KNOW that quick, huge, changes occured in the Earth's climate in the past.See other relevent posts in the past from Realclimate.Climate often does not change slowly, but undergoes huge, quick, changes periodically, due to negative feedbacks accumulating, and tipping the climate to a quick change.Why should the danger from huge potential methane releases be vievwed with any less trepidation?

Antarctic sea ice extent and concentration for January 2009 were up significantly over 1997, 34.8 % for ice extent & 22 % for ice concentration.

Measurements of air in ice cores show that for the past 800,000 years up until the 20th century, the atmospheric CO2 concentration stayed within the range 170 to 300 parts per million (ppm), making the recent rapid rise to nearly 400 ppm over 200 years particularly remarkable (see Figure 3).

Ice cores provide evidence for greenhouse gas concentration variations over the past 800,000 years (see the following section).

(Other sources: Atmospheric CO2 Concentrations over the Last Glacial Termination, New constraints on the gas age - ice age difference along the EPICA ice cores, 0â $ «50 kyr)

The models heavily relied upon by the Intergovernmental Panel on Climate Change (IPCC) had not projected this multidecadal stasis in «global warming»; nor (until trained ex post facto) the fall in TS from 1940 - 1975; nor 50 years» cooling in Antarctica (Doran et al., 2002) and the Arctic (Soon, 2005); nor the absence of ocean warming since 2003 (Lyman et al., 2006; Gouretski & Koltermann, 2007); nor the onset, duration, or intensity of the Madden - Julian intraseasonal oscillation, the Quasi-Biennial Oscillation in the tropical stratosphere, El Nino / La Nina oscillations, the Atlantic Multidecadal Oscillation, or the Pacific Decadal Oscillation that has recently transited from its warming to its cooling phase (oceanic oscillations which, on their own, may account for all of the observed warmings and coolings over the past half - century: Tsoniset al., 2007); nor the magnitude nor duration of multi-century events such as the Mediaeval Warm Period or the Little Ice Age; nor the cessation since 2000 of the previously - observed growth in atmospheric methane concentration (IPCC, 2007); nor the active 2004 hurricane season; nor the inactive subsequent seasons; nor the UK flooding of 2007 (the Met Office had forecast a summer of prolonged droughts only six weeks previously); nor the solar Grand Maximum of the past 70 years, during which the Sun was more active, for longer, than at almost any similar period in the past 11,400 years (Hathaway, 2004; Solankiet al., 2005); nor the consequent surface «global warming» on Mars, Jupiter, Neptune's largest moon, and even distant Pluto; nor the eerily - continuing 2006 solar minimum; nor the consequent, precipitate decline of ~ 0.8 °C in TS from January 2007 to May 2008 that has canceled out almost all of the observed warming of the 20th century.