Sentences with phrase «century periods of warm»

That the current temperature plateau follows a late 20th - century period of warming is consistent with the continuation today of natural multi-decadal or millennial climate cycling.

That current temperature plateau follows a late - 20th century period of warming consistent with... natural multi-decadal or millenial climate warming.»

Not exact matches

During the first third of the year, from January through April, the average temperature for the contiguous United States was 4 degrees Fahrenheit above the 20th - century average, making this period the second warmest on record, according to the National Oceanic and Atmospheric Administration.

Heavier rainfall at the study sites from the year 0 to 400, and again during Europe's Medieval Warm Period, just before the Little Ice Age from about the year 800 to 1300, was probably caused by a centuries - long strengthening of El Niño.

The surge in melt events corresponds to a summer temperature increase of at least 1.2 - 2 degrees Celsius (2.2 - 3.6 degrees Fahrenheit) relative to the warmest periods of the 18th and 19th centuries, with nearly all of the increase occurring in the last 100 years.

Short - lived climate pollutants are so called because even though they warm the planet more efficiently than carbon dioxide, they only remain in the atmosphere for a period of weeks to roughly a decade whereas carbon dioxide molecules remain in the atmosphere for a century or more.

But they looked for 50 - year - long anomalies; the last century's warming, the IPCC concludes, occurred in two periods of about 30 years each (with cooling in between).

In contrast, the consensus view among paleoclimatologists is that the Medieval Warming Period was a regional phenomenon, that the worldwide nature of the Little Ice Age is open to question and that the late 20th century saw the most extreme global average temperatures.

They concluded in the January Climate Research that «across the world, many records reveal that the 20th century is probably not the warmest nor a uniquely extreme climate period of the last millennium.»

The new analysis suggests no discernable decrease in the rate of warming between the second half of the 20th century, a period marked by manmade warming, and the first fifteen years of the 21st century, a period dubbed a global warming

According to the AAAS What We Know report, «The projected rate of temperature change for this century is greater than that of any extended global warming period over the past 65 million years.»

With ENSO - neutral conditions present during the first half of 2013, the January — June global temperature across land and ocean surfaces tied with 2003 as the seventh warmest such period, at 0.59 °C (1.06 °F) above the 20th century average.

The public, press and policy makers have been repeatedly told that three claims have widespread scientific support: Global temperature has risen about a degree since the late 19th century; levels of CO2 in the atmosphere have increased by about 30 % over the same period; and CO2 should contribute to future warming.

For the Quelccaya Ice Cap (13.95 oS, 70.83 oW), this work revealed that peak temperatures of the mediaeval warm period were warmer than those of the last few decades of the 20th century.»

peak temperatures of the mediaeval warm period were warmer than those of the last few decades of the 20th century»?

As discussed elsewhere on this site, modeling studies indicate that the modest cooling of hemispheric or global mean temperatures during the 15th - 19th centuries (relative to the warmer temperatures of the 11th - 14th centuries) appears to have been associated with a combination of lowered solar irradiance and a particularly intense period of explosive volcanic activity.

A confounding factor in discussions of this period is the unfortunate tendency of some authors to label any warm peak prior to the 15th Century as the «Medieval Warm Period» in their rperiod is the unfortunate tendency of some authors to label any warm peak prior to the 15th Century as the «Medieval Warm Period» in their recwarm peak prior to the 15th Century as the «Medieval Warm Period» in their recWarm Period» in their rPeriod» in their record.

For the late 20th century, a period of strong greenhouse gas increases, but with diminishing solar influence, variability in ocean warming shown in the profiles falls much further still.

The State of the Climate November 2015 report noted that in order for 2015 to not become the warmest year in the 136 - year period of record, the December global temperature would have to be at least 0.81 °C (1.46 °F) below the 20th century average — or 0.24 °C (0.43 °F) colder than the current record low December temperature of 1916.

If you look at the proxy portion of the new Moberg graphic, you see nothing that would be problematic for opponents of the hockey stick: it shows a striking Medieval Warm Period (MWP), a cold Little Ice Age and 20th century warming not quite reaching MWP levels by 1979, when the proxy portion of the study ends.

In the paper Gray makes many extravagant claims about how supposed changes in the THC accounted for various 20th century climate changes («I judge our present global ocean circulation conditions to be similar to that of the period of the early 1940s when the globe had shown great warming since 1910, and there was concern as to whether this 1910 - 1940 global warming would continue.

Simulations including an increased solar activity over the last century give a CO2 initiated warming of 0.2 ˚C and a solar influence of 0.54 ˚C over this period, corresponding to a CO2 climate sensitivity of 0.6 ˚C (doubling of CO2) and a solar sensitivity of 0.5 ˚C (0.1 % increase of the solar constant).

However, one of the panel's reservations was that ``... a statistical method used in the 1999 study was not the best and that some uncertainties in the work «have been underestimated,»...» The panel concluded «Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium.

This concatenation, which has global temperature 13.9 °C in the base period 1951 — 1980, has the first decade of the 21st century slightly (∼ 0.1 °C) warmer than the early Holocene maximum.

The public, press and policy makers have been repeatedly told that three claims have widespread scientific support: Global temperature has risen about a degree since the late 19th century; levels of CO2 [carbon dioxide] in the atmosphere have increased by about 30 percent over the same period; and CO2 should contribute to future warming.

There was a significant period of warming during the last 20 years of the 20th century, followed by a significant slowdown in warming during the 21st.

While periods of increased and decreased warming exist over the 132 - year period, the linear rate is still ~ 0.6 C / century, and the most recent monthly GISS values fall right on the linear trend (the linear trend value for the Feb. 2012 temperature anomaly is +0.38 C, while the last two months have been +0.35 and +0.40 C.)

-- The combined global land and ocean average surface temperature for the December — February period was 0.41 °C (0.74 °F) above the 20th century average of 12.1 °C (53.8 °F), making it the 17th warmest such period on record and the coolest December — February since 2008.

The annual temperature history of the United States during the 20th century shows three distinct periods of change: warming from 1900 until about 1940, cooling from 1940 to 1969, and warming from 1970 to the present.

A quick search turns up this partially relevant paper, which notes the influence of warming of currents in the North Atlantic, beginning in the early part of the 20th century, and which reminds us that the 60s were the most marked «cool» decade of the post-war period:

While periods of increased and decreased warming exist over the 132 - year period, the linear rate is still ~ 0.6 C / century

Simulations including an increased solar activity over the last century give a CO2 initiated warming of 0.2 ˚C and a solar influence of 0.54 ˚C over this period, corresponding to a CO2 climate sensitivity of 0.6 ˚C (doubling of CO2) and a solar sensitivity of 0.5 ˚C (0.1 % increase of the solar constant).

A long term study of climactic conditions would place the first half of the twentieth century into an exceptionally warm period.

The fact remains that the rate of warming in the early 20th century is comparable to that in the late 20th century whether you look at the Arctic in isolation or the globe as a whole and since CO2 levels were markedly different in the 2 periods there must be another significant factor.

However, as I understand it what is currently the mainstream view is that what explains the transition from early 20th century warming to the flat period between is the resumption of industrial production and thus of reflective aerosols (predominantly sulfates), and that likewise, it was the passage in the early seventies of laws requiring cleaner emissions that reduced reflective aerosols.

For over half the locations analyzed, warming at least triples the odds of century - plus floods over the same period.

I would like to see discussion about the most recent period of rapid global warming... leading to the Paleocene Eocene Thermal Maximum (PETM) about 55 million years ago... including differences and similarities to the climate projections for this century... and beyond.

Temperatures have been rising since the 19th century, with periods of greater and lesser warming (even cooling).

These warming periods, however, did not approach the anticipated warming of this century.

«We show that the climate over the 21st century can and likely will produce periods of a decade or two where the globally averaged surface air temperature shows no trend or even slight cooling in the presence of longer - term warming,» the paper says, adding that, «It is easy to «cherry pick» a period to reinforce a point of view.»

The authors clearly identify a long - term warming from the Last Glacial Maximum, a mid-Holocene warm episode, the Medieval Warm Period, the Little Ice Age, and the rapid warming of the twentieth centwarm episode, the Medieval Warm Period, the Little Ice Age, and the rapid warming of the twentieth centWarm Period, the Little Ice Age, and the rapid warming of the twentieth century.

If there was more natural variation in the past millenia, specifically due to solar changes, then that goes at the cost of the GHG / aerosol combination, as both are near impossible to distinguish from each other in the warming of the last halve century... Solar activity has never been as high, and for an as long period, as current in the past millenium (and even the past 8,000 years).

Given the total irrelevance of volcanic aerosols during the period in question, the only very modest effect of fossil fuel emissions and the many inconsistencies governing the data pertaining to solar irradiance, it seems clear that climate science has no meaningful explanation for the considerable warming trend we see in the earlier part of the 20th century — and if that's the case, then there is no reason to assume that the warming we see in the latter part of that century could not also be due to either some as yet unknown natural force, or perhaps simply random drift.

SAT observations and model simulations indicate that the nature of the arctic warming in the last two decades is distinct from the early twentieth - century warm period.

[14] Although there is an extreme scarcity of data from Australia (for both the Medieval Warm Period and Little Ice Age) evidence from wave built shingle terraces for a permanently full Lake Eyre during the ninth and tenth centuries is consistent with this La Niña - like configuration, though of itself inadequate to show how lake levels varied from year to year or what climatic conditions elsewhere in Australia were like.

For most recent sampling see: New Peer - Reviewed Study finds «Solar changes significantly alter climate» (11-3-07)(LINK) & «New Peer - Reviewed Study Halves the Global Average Surface Temperature Trend 1980 — 2002» (LINK) & New Study finds Medieval Warm Period «0.3 C Warmer than 20th Century» (LINK) For a more comprehensive sampling of peer - reviewed studies earlier in 2007 see «New Peer - Reviewed Scientific Studies Chill Global Warming Fears» LINK]

We were talking about recent centuries, and you bring in a whole lot of random references to the Medieval Warm Period?

«A significant share of the warming we saw from 1980 to 2000 and at earlier periods in the 20th Century was due to these cycles â $ «perhaps as much as 50 per cent.

«The entire satellite data for the whole world shows a warming during the 1979 - 2002 period of just 0.005 º C by year, or 0.5 º C in a century.

(Reference 1) During these warm periods, there are cycles of relatively cold weather such as the Maunder Minimum during the mid-seventeenth century.