Sentences with phrase «ended past ice ages»

Not exact matches

The overall retreat of several kilometers that has occurred over the past 20,000 years was interrupted by a stillstand or a re-advance of several hundred years at the beginning of the ACR, and then by increasingly minor glacial episodes at the end of the YD, at the beginning of the Holocene (around 10,000 years ago) and during the Little Ice Age (13th to 19th centuries).

On land, the capacity of animals to carry nutrients away from concentrated «hotspots,» the team writes, has plummeted to eight percent of what it was in the past — before the extinction of some 150 species of mammal «megafauna» at the end of the last ice age.

There have been several such transitions in the past, but one of the largest and most dramatic transitions happened at the end of the last Ice Age.

Geologists knew of some fairly widespread glaciations in the past: there was an ice - age at the end of the Ordovician period, some 445 million years back and, going further back again, there were some huge, perhaps planet - wide glaciations in the Proterozoic eon.

It is my understanding that the previous ice ages have ended in the past by a forcing from changes in tilt of the earth (i.e. Milankovitch cycles).

The paper, combining evidence of driftwood accumulation and beach formation in northern Greenland with evidence of past sea - ice extent in parts of Canada, concludes that Arctic sea ice appears to have retreated far more in some spans since the end of the last ice age than it has in recent years.

Your incorrect claim that the current climate change «is unprecedented perhaps over the past 100,000 years» is incorrect, because it ignores that huge, incredibly rapid change at the end of the ice age, which was survived by all of the species that we know and love.

At the beginning of the Holocene - after the end of the last Ice Age - global temperature increased, and subsequently it decreased again by 0.7 ° C over the past 5000 years.

There is still some discussion about how exactly this starts and ends ice ages, but many studies suggest that the amount of summer sunshine on northern continents is crucial: if it drops below a critical value, snow from the past winter does not melt away in summer and an ice sheet starts to grow as more and more snow accumulates.

In the past few centuries, smaller transitions (such as the ending of the Little Ice Age at about 1650 AD) probably occurred over only a few decades at most.

What «sea - level rise» alarmists won't tell you is that seas have risen 400 feet (120m) over the past 20,000 years, since the end of the last Ice Age.

Sea levels have been increasing since the end of the last ice age, and the rate of change is near the lowest in the past 15,000 years.

This modern Warm time is much like all the Warm times in the past ten thousand years and it will end and be followed by another little ice age.

Although the I.P.C.C. allowed for the possibility that variations in sunlight could have ended the «Little Ice Age,» a period of cooling from the 14th century to about 1850, our data argues strongly that the temperature rise of the past 250 years can not be attributed to solar changes.

For roughly the past 10,000 years, since the end of the last Ice Age, human beings have enjoyed a relatively stable, comfortable «interglacial» period, during which they've invented everything from agriculture to moon rockets.

report that ocean sediment cores containing an «undisturbed history of the past» have been analyzed for variations in PP over timescales that include the Little Ice Age... they determined that during the LIA the ocean off Peru had «low PP, diatoms and fish,» but that «at the end of the LIA, this condition changed abruptly to the low subsurface oxygen, eutrophic upwelling ecosystem that today produces more fish than any region of the world's oceans... write that «in coastal environments, PP, diatoms and fish and their associated predators are predicted to decrease and the microbial food web to increase under global warming scenarios,» citing Ito et al..

Such oceanic temperature as now subsists would probably be a historical inheritance from a long past state possibly at the end of the last ice age when it was reset by a combination of changed energy throughput from the sun plus the resistor effect of the oceans and air combined with the then state of the air circulation.

What is more, the Sun has been more active and for longer over the last 70 years than at almost any previous similar period over the past 11,400 years since the end of the last ice age.

Have global temperatures — and please listen to the question carefully — have global overall temperatures increased in the past 50 years — not the past 100 years — because we know the temperatures globally rose after the end of the Little Ice Age in the 1700s, and that global temperatures have risen about 1 degree Celsius in the past 100 years.

According to the report, which follows a series of comprehensive reports from the IPCC in the past year on climate science and impacts, temperatures already have increased by 0.85 degrees Celsius since 1880, a more rapid shift in the climate than that which heralded the end of the last ice age about 10,000 years ago.

Here, we argue that the twentieth and twenty - first centuries, a period during which the overwhelming majority of human - caused carbon emissions are likely to occur, need to be placed into a long - term context that includes the past 20 millennia, when the last Ice Age ended and human civilization developed, and the next ten millennia, over which time the projected impacts of anthropogenic climate change will grow and persist.

Scientific records over the past million years show that as periodic ice ages ended, global average temperatures rose a total of 4 - 7 degrees Celsius over the course of about 5,000 years.

10 Temperature change over past 22,000 years Agriculture established Temperature change (C °) End of last ice age Average temperature over past 10,000 years = 15 °C (59 °F) Figure 20.2 Science: estimated changes in the average global temperature of the atmosphere near the earth's surface over different periods of time.

But what caught my eye was a really interesting companion article, highlighting research on Roman seaside ruins which indicate that for the past two millennia or so that sea levels have been comparatively steady, and that the level of increase we witness today really started with industrialization.Though there's no doubt that sea levels around the globe have fluctuated widely, as in hundreds of foot differences — at the end of last ice age when ice sheets melted sea level rose almost 400 feet.

Have a look at this updated version of one of the articles here about past temperatures, it has good graphics and more detail about determining the past, plus links to good sources: http://gristmill.grist.org/story/2006/10/26/20495/240 The warming that ended the ice age was caused by changes in the earth's orbital inclination (Milankovich cycles).

In this case, the authors have produced a testable forecast of the past climate by leaving out the period between the end of the last ice age and up to 4000 years before present.

Geologists knew of some fairly widespread glaciations in the past: there was an ice - age at the end of the Ordovician period, some 445 million years back and, going further back again, there were some huge, perhaps planet - wide glaciations in the Proterozoic eon.

Argues that the twentieth and twenty - first centuries, a period during which the overwhelming majority of human - caused carbon emissions are likely to occur, need to be placed into a long - term context that includes the past 20 millennia, when the last Ice Age ended and human civilization developed, and the next ten millennia, over which time the projected impacts of anthropogenic climate change will grow and persist