Sentences with word «palaeoclimatic»

Secondly, we have lots of palaeoclimatic evidence for abrupt changes in the AMOC, which are leading candidates to explain Dansgaard - Oeschger transitions during the last ice age, and the cold snap 8,200 years ago.

Individual decadal - resolution palaeoclimatic data sets support the existence of regional quasi-periodic climate variability, but it is unlikely that these regional signals were coherent at the global scale.

Here we briefly discuss the radiative forcing estimates used for understanding climate during the last millennium, the mid-Holocene and the Last Glacial Maximum (LGM)(Section 9.3) and in estimates of climate sensitivity based on palaeoclimatic records (Section 9.6.3).

Palaeoclimatic studies rely on multiple proxies so that results can be cross-verified and uncertainties better understood.

Figure 1: Northern Hemisphere temperatures were reconstructed for the past 1000 years (up to 1999) using palaeoclimatic records (tree rings, corals, ice cores, lake sediments, etc.), along with historical and long instrumental records (WMO 2000).

Modeling the epidemiological history of plague in Central Asia: Palaeoclimatic forcing on a disease system over the past millennium.

Hegerl et al. (2006a) is based on multiple palaeoclimatic reconstructions of NH mean temperatures over the last 700 years.

Advancing tephrochronology as a global dating tool: Applications in volcanology, archaeology, and palaeoclimatic research Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located

Their work may help resolve intense debate surrounding palaeoclimatic records and model projections [continue reading...]

Similar oscillations in a 60 - to 110 - year band are seen in North Atlantic palaeoclimatic reconstructions through the last four centuries (Delworth and Mann, 2000; Gray et al., 2004).

These analyses are complemented by sensitivity analysis of the spatial representativeness of available palaeoclimatic data, indicating that the warmth of the recent decade is outside the 95 % confidence interval of temperature uncertainty, even during the warmest periods of the last millennium.

Abstract «Although we conclude, as found elsewhere, that recent warming has been substantial relative to natural fluctuations of the past millennium, we also note that owing to the spatially heterogeneous nature of the MWP, and its different timing within different regions, present palaeoclimatic methodologies will likely «'' flatten out» estimates for this period relative to twentieth century warming, which expresses a more homogenous global «'' fingerprint.»

Cook, E.R., J.G. Palmer, B.I. Cook, A. Hogg, and R.D. D'Arrigo, 2002: A multi-millennial palaeoclimatic resource from Lagarostrobos colensoi tree - rings at Oroko Swamp, New Zealand.

The corresponding future temperatures in Greenland (1.9 to 4.6 °C global) are comparable to those inferred for the last interglacial period 125,000 years ago, when palaeoclimatic information suggests reductions of polar land ice extent and 4 to 6m of sea level rise.

Development of International Palaeoclimatic data network

To define medieval warmth in a way that has more relevance for exploring the magnitude and causes of recent large - scale warming, widespread and continuous palaeoclimatic evidence must be assimilated in a homogeneous way and scaled against recent measured temperatures to allow a meaningful quantitative comparison against 20th - century warmth (Figure 6.10).

The atmospheric CO2 concentration was however higher in Earth's more distant past (many millions of years ago), at which time palaeoclimatic and geological data indicate that temperatures and sea levels were also higher than they are today.

There are very few palaeoclimatic records for these latter two regions.»

The team searched for climate fluctuations in high - resolution palaeoclimatic records that are associated with current - day plague outbreaks in major host species (such as the great gerbil Rhombomys opimus), and found such fluctuations to statistically relate with reintroductions of plague into medieval Europe.

Palaeoclimatic studies make use of measurements of past change derived from borehole temperatures, ocean sediment pore - water change and glacier extent changes, as well as proxy measurements involving the changes in chemical, physical and biological parameters that reflect past changes in the environment where the proxy grew or existed.

In addition, a growing set of palaeoclimatic data, e.g., from trees, corals, sediments, and ice, are giving information about the Earth's climate of centuries and millennia before the present.

Here we briefly discuss the radiative forcing estimates used for understanding climate during the last millennium, the mid-Holocene and the Last Glacial Maximum (LGM)(Section 9.3) and in estimates of climate sensitivity based on palaeoclimatic records (Section 9.6.3).

This work applies novel organic and inorganic geochemical proxies for palaeoclimatic and palaeoenvironmental reconstruction and makes use of samples collected through deep - sea scientific drilling and extensive fieldwork.

We need to learn from the palaeoclimatic record.

The palaeoclimatic records of northern and eastern Africa and of North America indicate that droughts lasting decades to centuries are a recurrent feature of climate in these regions, so that recent droughts in North America and northern Africa are not unprecedented.

Palaeoclimatic data provide evidence for changes in many regional climates.

However, palaeoclimatic data are more limited than the instrumental record since 1850 in both space and time, so that statistical methods are employed to construct global averages, and these are subject to uncertainties as well.

This result sheds new light on the effect of long - term fertilization by iron and macronutrients on carbon sequestration, suggesting that changes in iron supply from belowâ as invoked in some palaeoclimatic and future climate change scenarios11â may have a more significant effect on atmospheric carbon dioxide concentrations than previously thought.

However, palaeoclimatic evidence (Denman et al., 2007 Sections 6.4.3.2 and 6.4.3.3; Overpeck et al., 2006; Otto - Bliesner et al., 2006) suggests that Greenland and possibly the WAIS contributed to a sea - level rise of 4 - 6 m during the last interglacial, when polar temperatures were 3 - 5 °C warmer, and the global mean was not notably warmer, than at present (Meehl et al., 2007 Sections 10.7.4.3 and 10.7.4.4).

For example, deductive reasoning would ask the question — if CO2 causes runaway and dangerous warming, then what evidence do we see of this in the palaeoclimatic record of the Ordovician era where CO2 levels in the atmosphere were 8 - 20 times higher than today.

Palaeoclimatic and archaeological evidence for a 200 - yr recurrence of floods and droughts linking California, Mesoamerica and South America over the past 2000 years (The Holocene, Volume 13, Number 5, pp. 763 - 778, 2003)-- Amdt Schimmelmann et al..