Sentences with phrase «present atmospheric levels»

The global average temperature is already approximately 0.8 °C above its preindustrial level, and present atmospheric levels of greenhouse gases will contribute to further warming of 0.5 — 1 °C as equilibrium is re-established.

Simple sponges can live with 200 times less oxygen than present atmospheric levels, supporting the idea that animals evolved before oxygen - rich oceans

Not exact matches

The model suggests atmospheric oxygen was likely at around 10 % of present day levels during the two billion years following the Great Oxidation Event, and no lower than 1 % of the oxygen levels we know today.

The ice core data also shows that CO2 and methane levels have been remarkably stable in Antarctica — varying between 300 ppm and 180 ppm — over that entire period and that shifts in levels of these gases took at least 800 years, compared to the roughly 100 years in which humans have increased atmospheric CO2 levels to their present high.

There was virtually no atmospheric O2 present 3.4 billion years ago, but recent work from South African paleosols suggested that by about 2.96 billion years ago O2 levels may have begun to increase.

Most important, how did the amount of atmospheric oxygen reach its present level?

This dynamic time for East Antarctic glaciers occurred when atmospheric temperatures and atmospheric CO2 levels were similar to or higher than present day.

Although atmospheric oxygen soon recovered again as photosynthesis and weathering reached a new balance, at about 10 per cent of present - day levels, the oxidative weathering of sulphides on land filled the oceans with sulphate which created abundant food for a group of bacteria that filled the oceans with sewer gas (hydrogen sulphide) toxic to oxygen - loving lifeforms (delaying the development of eukaryotic plants and animals) and turned them «into stinking, stagnant waters almost entirely devoid of oxygen.»

The installations in this exhibition expanded the possibilities of Julien's art, permitting him to create atmospheric, complex environments that engaged viewers on multiple levels and presented an alternative to the centred view of the single - screen projection.

In view of the present discussion of the role of carbon dioxide in effecting global temperature I would like to know of any laboratory or bench experiments that show a temperature - CO2 concentration curve within the range of currently measured atmospheric CO2 levels.

These measurements, supplemented by analyses of air bubbles trapped in ice core samples, show unequivocally that atmospheric CO2 has increased from a pre-industrial level of 277 ppm in 1750 to present day concentrations that are approaching 390 ppm.

«This perspective article focuses on intervals in time in the fossil record when atmospheric CO2 concentrations increased up to 1200 ppmv, temperatures in mid - to high - latitudes increased by greater than 4 °C within 60 years, and sea levels rose by up to 3 m higher than present.

On another subject, now that we know from Al Gore's researches, that our SUVs, which keep raising the CO2 levels at Mauna Loa, are the direct cause of the Mediaeval Warm Period (remember that was just 800 years before the present rising CO2 event); we can predict with near certainty, that when everybody who signed on to the Kyoto accords, meets their obligations, resulting in a coming dearth of atmospheric CO2, that is going to directly cause an event which will become known as the little ice age which happened in the 1600 to 1840 time range.

We present a large - scale Southern Ocean observational analysis that examines the seasonal magnitude and variability CO32 − and pH. Our analysis shows an intense wintertime minimum in CO32 − south of the Antarctic Polar Front and when combined with anthropogenic CO2 uptake is likely to induce aragonite undersaturation when atmospheric CO2 levels reach ≈ 450 ppm.»

In order to determine the rate of historical responsiveness to atmospheric levels of CO2, it is essential to use high - resolution SI data that (i) have not been significantly affected by influences of environmental conditions other than CO2values, and (ii) that can be calibrated against the (1958 — present) Mauna Loa record of increases of atmospheric CO2 levels.

John Carter August 8, 2014 at 12:58 am chooses to state his position on the greenhouse effect in the following 134 word sentence: «But given the [1] basics of the greenhouse effect, the fact that with just a very small percentage of greenhouse gas molecules in the air this effect keeps the earth about 55 - 60 degrees warmer than it would otherwise be, and the fact that through easily recognizable if [2] inadvertent growing patterns we have at this point probably at least [3] doubled the total collective amount in heat absorption and re-radiation capacity of long lived atmospheric greenhouse gases (nearly doubling total that of the [4] leading one, carbon dioxide, in the modern era), to [5] levels not collectively seen on earth in several million years — levels that well predated the present ice age and extensive earth surface ice conditions — it goes [6] against basic physics and basic geologic science to not be «predisposed» to the idea that this would ultimately impact climate.»

Here it is useful to note that an atmospheric concentration level close to 550 ppm CO2e would result by 2050 if greenhouse gas emissions simply continued at present levels without any increases in the intervening years.

The costs to the world economy of ensuring that atmospheric CO2e stabilized at present levels or below would be prohibitive, destabilizing capitalism itself.

Quantitatively, Vasskog et al. estimate that during this time (the prior interglacial) the GrIS was «probably between ~ 7 and 60 % smaller than at present,» and that that melting contributed to a rise in global sea level of «between 0.5 and 4.2 m.» Thus, in comparing the present interglacial to the past interglacial, atmospheric CO2 concentrations are currently 30 % higher, global temperatures are 1.5 - 2 °C cooler, GrIS volume is from 7 - 67 % larger, and global sea level is at least 0.5 - 4.2 m lower, none of which observations signal catastrophe for the present.

C: increase in atmospheric CO2 from pre-industrial to present is anthropogenic (D / A) S: best guess for likely climate sensitivity (NUM) s: 2 - sigma range of S (NUM) a: ocean acidification will be a problem (D / A) L: expected sea level rise by 2100 in cm (all contributions)(NUM) B: climate change will be beneficial (D / A) R: CO2 emissions need to be reduced drastically by 2050 (D / A) T: technical advances will take care of any problems (D / A) r: the 20th century global temperature record is reliable (D / A) H: over the last 1000 years global temperature was hockey stick shaped (D / A) D: data has been intentionally distorted by scientist to support the idea of anthropogenic climate change (D / A) g: the CRU - mails are important for the science (D / A) G: the CRU - mails are important otherwise (D / A)

Claims now proven false include; • an increase in CO2 precedes a temperature increase; • current atmospheric levels of CO2 are the highest on record; • and pre-industrial levels of CO2 were approximately 100 parts ppm lower than the present 385 ppm.

Based on proxy records from ice, terrestrial and marine archives, the LIG is characterized by an atmospheric CO2 concentration of about 290 ppm, i.e., similar to the pre-industrial (PI) value13, mean air temperatures in Northeast Siberia that were about 9 °C higher than today14, air temperatures above the Greenland NEEM ice core site of about 8 ± 4 °C above the mean of the past millennium15, North Atlantic sea - surface temperatures of about 2 °C higher than the modern (PI) temperatures12, 16, and a global sea level 5 — 9 m above the present sea level17.

They include: (1) a 35 year US delay on climate action has made the problem extraordinarily challenging to solve, (2) US greenhouse gas (ghg) emissions are more than any country responsible for rise in atmospheric concentrations to present dangerous levels, (3) US ghg emissions not only threaten the US with climate disruption but endanger many of the poorest people around the world, (4) the Obama administration's pledge to reduce ghg emissions is far short of the US fair share of safe global emissions.

Current atmospheric CO2 levels are higher than at any time since at least a million years ago, and there is no notable scientific dissent from the consensus position that global warming is happening, is human caused, and presents a global problem.

At present levels of atmospheric CO2 increases to the CO2 have no significant effect on global temperature.

So, as the empirical measurements which I cited for you show, at present levels of atmospheric CO2 increases to the CO2 have no significant effect on global temperature.

For the purpose of simplifying the argument, STT is happy to concede that man - made CO2 emissions may cause an increase in atmospheric temperatures — whether or not modest increases in atmospheric temperature from present levels represents a threat to humans or the planet is another question again (see our post here).

Even if greenhouse gases never rise beyond their present level, temperatures and sea levels will continue rising for another century or more because of a time lag in the oceans» response to atmospheric temperatures, say researchers.

Since the start of the Industrial Age, atmospheric carbon dioxide levels have increased by over 35 per cent, from the long - term range of 260 - 280 parts per million (ppm) to the present level of over 380 ppm.

The CO2 tectonic source grew from 60 to 50 Myr BP as India subducted carbonate - rich ocean crust while moving through the present Indian Ocean prior to its collision with Asia about 50 Myr BP [8], causing atmospheric CO2 to reach levels of the order of 1000 ppm at 50 Myr BP [9].

Our present approach of dealing with climate as completely specified by a single number, globally averaged surface temperature anomaly, that is forced by another single number, atmospheric CO2 levels, for example, clearly limits real understanding; so does the replacement of theory by model simulation.

ACIA, in this graphic, manage to present virtually a perpendicular change which gives the impression of being about 500 % over «background» levels and fitted neatly to a representation of the infamous «hockey stick» graph when in fact the total change in atmospheric carbon dioxide is under 35 %.

The carbon they refer to is Carbon dioxide, / CO2 a gaseous product of the burning of practically any combustible product of this planet and a gas which if the planet lacked or was not present at a sufficiently high atmospheric level and had remained so for countless millenniums past, no sentient life or plant life would exist today.

Taken together, the average of the warmest times during the middle Pliocene presents a view of the equilibrium state of a globally warmer world, in which atmospheric CO2 concentrations (estimated to be between 360 to 400 ppm) were likely higher than pre-industrial values (Raymo and Rau, 1992; Raymo et al., 1996), and in which geologic evidence and isotopes agree that sea level was at least 15 to 25 m above modern levels (Dowsett and Cronin, 1990; Shackleton et al., 1995), with correspondingly reduced ice sheets and lower continental aridity (Guo et al., 2004).

However, at present atmospheric aerosol levels are very low indeed, with the OD550 being lower than anytime in 30 + years.

By adding carbon to this system, we are responsible for essentially all of the increase in the level of atmospheric CO2 that has occurred since the start of the industrial revolution, which is at present about a 40 % increase.

The Pliocene is a paradox when compared to other Cenozoic warm intervals because global mean temperatures were 2 — 3 °C warmer than present (Dowsett, 2007), despite levels of atmospheric CO2 that were only slightly higher than preindustrial levels (Fedorov et al., 2006).

Although historical records indicate that atmospheric CO2 concentrations and sea surface temperatures have undergone significant oscillations and have exceeded present - day levels in the past [3,4], it is the unprecedented rates of change that are fuelling concerns over whether organisms will retain the capacity to mediate vital ecosystem functions and services [5,6].

In presenting the «embers» in the TAR, IPCC authors did not assess whether any single RFC was more important than any other; nor did they conclude what level of impacts or what atmospheric concentrations of greenhouse gases would constitute DAI, a value judgment that would be policy prescriptive.