Sentences with phrase «century warming therefore»
However, it would be naive to conclude that the observed strong 20th Century warming therefore also must have a natural cause.
http://www.realclimate.org/ Not exact matches
Therefore, the solar forcing combined with the anthropogenic CO2 forcing and other minor forcings (such as decreased volcanic activity) can account for the 0.4 °C warming in the early 20th century, with the solar forcing accounting for about 40 % of the total warming.
Therefore, with all other variables being equal, I would suggest a more rapid warming towards the latter part of this century, that is, given the plausibility of the former conjecture.
Therefore the timing of the onset of glacier retreat implies that a significant global warming is likely to have started not later than the mid-19th century.
«What I see, therefore is not a long term warming trend, covering all or most of the 20th century,........
We can, therefore, compare the present warming trends (and warming / cooling cycles; think about the «mini-ice age» of the 19th Century) with the geological record and make statistical extrapolations about changing rates and develop hypotheses about causes (whichh, basically, is what current climate scientists have been doing).
http://www.realclimate.org/index.php/archives/2005/08/did-the-sun-hit-record-highs-over-the-last-few-decades/ «Regardless of any discussion about solar irradiance in past centuries, the sunspot record and neutron monitor data (which can be compared with radionuclide records) show that solar activity has not increased since the 1950s and is therefore unlikely to be able to explain the recent warming.»
Victor's original premise that we do not understand the warming of the first half of the last century therefore this sheds doubt on AGW is completely false.
[edit] On the contrary, there are overwhelming evidences from several independent studies that the middle age was quite warm and that the 16 / 17th centuries were quite cold, this would strongly support Moberg reconstruction and therefore the conclusion of above (and my estimates).
But the evidence shows this can't be true; temperature changes before CO2 in every record of any duration for any time period; CO2 variability does not correlate with temperature at any point in the last 600 million years; atmospheric CO2 levels are currently at the lowest level in that period; in the 20th century most warming occurred before 1940 when human production of CO2 was very small; human production of CO2 increased the most after 1940 but global temperatures declined to 1985; from 2000 global temperatures declined while CO2 levels increased; and any reduction in CO2 threatens plant life, oxygen production, and therefore all life on the planet.
It seems likely to me that the level warming we have had in many periods of this interglacial period are likely to occur again in the future centuries: And it seems during most the current of the interglacial temperatures have as warm or warmer than current temperatures, therefore it seems as warmer or warmer is most likely.
Most of the rural cities in my state show no warming at all since 1890 - 1895 when the records began but this is but one area and maybe it has some special properties that protect it, or shield it, from this assumed increase in accumulated global energy (therefore a raising of temperature) but in physics I learned that is not possible over a century of time even in a system even as large as the entire Earth.
Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long - term cooling trend that began ~ 5000 yr B.P.
Therefore, our results confirm that positive radiative forcings (e.g., from human - caused increases in greenhouse gas concentrations) are necessary in order for the Earth to have warmed as much as it did over the 20th century.
Marcott paper Basically the folks at RC have probably made poor ol Marcott respond that the uptick did not matter anyway its not important, significant, robust etc don't rely on it just forget about it please etc but unfortunately for them as Ross MC on Realclimate reply, at CA says «But that is precisely what they do in Figure 3 of their paper, and it is the basis of their claim that «Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long - term cooling trend that began ~ 5000 yr B.P.» Without the uptick in their proxy reconstruction this kind of statement could never have been made.
«Alec Rawls says;... Muscheler's that I was paraphrasing (with emphasis added): ``... Solar activity & cosmic rays were relatively constant (high solar activity, strong shielding and low cosmic rays) in the second part of the 20th century and, therefore, it is unlikely that solar activity (whatever process) was involved in causing the warming since 1970...»
CH4 is relatively short - lived in the atmosphere (atmospheric lifetime on the order of a decade) relative to CO2 (atmospheric lifetime on the order of centuries) and therefore has a higher global warming potential over the shorter 20 - year time horizon (86 versus 34; Myhre et al. 2013).
IPCC has stated (AR4 WG1 Ch.9) that the «global mean warming observed since 1970 can only be reproduced when models are forced with combinations of external forcings that include anthropogenic forcings... Therefore modeling studies suggest that late 20th - century warming is much more likely to be anthropogenic than natural in origin...» whereas for the statistically indistinguishable early 20thC warming period «detection and attribution as well as modeling studies indicate more uncertainty regarding the causes of early 20th - century warming.»
Therefore, Miskolczi concludes that the observed increase in CO2 concentration must not be the reason for global warming of the last century.
This is contrary to the Medieval Climate Anomaly (MCA), which had reduced variability and therefore may be misleading as an analog for 21st century warming, notwithstanding its warm (and arid) conditions.
This north / south asymmetry has grown since perihelion was aligned with the winter solstice seven to eight centuries ago, and must cause enhanced year - on - year springtime melting of Arctic (but not Antarctic) ice and therefore feedback warming because increasing amounts of land and open sea are denuded of high - albedo ice and snow across boreal summer and into autumn.
Subject to the above caveats and those described in the text, the CRF / climate link therefore implies that the increased solar luminosity and reduced CRF over the previous century should have contributed a warming of 0.47 ± 0.19 ° K, while the rest should be mainly attributed to anthropogenic causes.
Some of the late 20th century warming is therefore from a solar heat lag from the increase in solar output from 1750 - 1950 +, meaning C02 effect is even weaker than in your paper above.
It was discovered more than a century ago that burning fossil fuels would release warming gases and therefore increase global temperatures, and since then, hundreds of thousands of scientists have independently reached the conclusion that it will have terrible consequences...
But that is precisely what they do in Figure 3 of their paper, and it is the basis of their claim that «Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long - term cooling trend that began ~ 5000 yr B.P.» Without the uptick in their proxy reconstruction this kind of statement could never have been made.
Their summary statement is: «Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long - term cooling trend that began ~ 5000 yr B.P.»
I am impressed by the chutzpah of your logic, that because 0.64 % of all scientists holding a Phd have signed a petition denying the science, that therefore it is not true that 97 % of climate scientists agree that humans have caused the late twentieth century warming.
«It will therefore be prudent to further reduce the flow of anthropogenic [human - created] nutrients to Walden Pond under the warmer, wetter conditions that most climate models project for New England during the 21st century.»
Therefore, modelling studies suggest that late 20th - century warming is much more likely to be anthropogenic than natural in origin, a finding which is confirmed by studies relying on formal detection and attribution methods (Section 9.4.1.4).»
Medieval warm periods in Europe and Asia with temperatures comparable to those seen in the 20th century were therefore similarly plausible but might have been local phenomena: the report noted «the magnitude and geographic extent of the warmth are uncertain.»
Therefore if what is meant by global warming means is earth's average temperature has been rising for more than century, the burden of proof can't be that there is no human influence.
A more likely scenario for interpretation of the observed warming of the early 20th century might be a smaller (and therefore more likely) realization of internal variability coupled with additional external radiative forcings.
Therefore, the solar forcing combined with the anthropogenic CO2 forcing and other minor forcings (such as decreased volcanic activity) can account for the 0.4 °C warming in the early 20th century, with the solar forcing accounting for about 40 % of the total warming.