Sentences with phrase «atmospheric concentration by»

I am glad though to find someone who accepts the overwhelming evidence that mans emssions have increased CO2 atmospheric concentration by 40 %.

Even though the non-natural source is less than 2 % of the natural source, it has, over time, increased the atmospheric concentration by 33 %.

It is misleading to refer to CO2 emissions that do not increase atmospheric concentration by 100 percent of their value as «missing».

Scientists can determine ancient atmospheric concentrations by measuring CO2 and methane levels in tiny air bubbles trapped in such ice, formed when the ice fell to the earth as snow.

Not exact matches

The atmospheric concentration of benzene, for example, decreased by about 6,000 times, dramatically improving air quality.

After allowing for humidity and rainfall, they found that «aerosol optical thickness» — a measure of the concentration of atmospheric particles — decreased by only 10 to 15 per cent compared with the same periods in 2002 to 2007 (Geophysical Research Letters, in press).

Curiously, the decline in atmospheric oxygen over the past 800,000 years was not accompanied by any significant increase in the average amount of carbon dioxide in the atmosphere, though carbon dioxide concentrations do vary over individual ice age cycles.

«They are using this information to test state - of - the - art climate models under conditions of high atmospheric carbon dioxide concentrations, similar to those expected by the end of this century.»

This human habit has already shifted atmospheric CO2 concentrations by more than 100 parts per million, which is the usual shift in concentration between a planet swathed in ice and the more temperate climes in which human civilization developed.

«Which of those is correct at this stage is unknown, but the droughts being driven by atmospheric greenhouse gas concentrations is in line with some of these global circulation models,» Lewis said.

The team used the data from charcoal in coal to propose that the development of fire systems through this interval was controlled predominantly by the elevated atmospheric oxygen concentration (p (O2)-RRB- that mass balance models predict prevailed.

During the early 2000s, environmental scientists studying methane emissions noticed something unexpected: the global concentrations of atmospheric methane (CH4)-- which had increased for decades, driven by methane emissions from fossil fuels and agriculture — inexplicably leveled off.

A proposal we had co-authored with Chet Spicer (Battelle, Columbus, Ohio) to directly measure gaseous halogen concentrations by using atmospheric pressure chemical ionization (APCI) mass spectrometry in the early arctic spring was gratuitously funded at the eleventh hour, and Finlayson - Pitts asked me to participate in the field work despite the fact that I had no previous experience in field research.

Over the past 250 years, human activities such as fossil fuel burning have raised the atmospheric CO2 concentration by more than 40 % over its preindustrial level of 280 ppm (parts per million).

According to the study, the models project that ocean warming will be even more pronounced than suggested by coarser models under increasing concentrations of atmospheric CO2.

For their scenario calculations, the AWI modellers plugged in atmospheric CO2 concentrations in excess of 500 ppm, a level in keeping with the forecasts released by the Intergovernmental Panel on Climate Change (IPCC).

With coordinated experiments with six atmospheric general circulation models, forced by observed daily sea - ice concentration and sea surface temperatures.

Averaged over the entire globe, it's one - fourth as large as the heating caused by increasing atmospheric CO2 concentrations during the same period.

The Scripps Institution of Oceanography records of atmospheric carbon dioxide levels show that Jan. 1 was the first day of the new year above that concentration, followed by Jan. 3 and Jan. 7.

Estimated effects of future atmospheric CO2 concentrations on protein intake and the risk of protein deficiency by country and region.

Their assessment revealed a consistent picture of increasing nitrate concentrations, the magnitude and pattern of which can only be explained by the observed increase in atmospheric nitrogen deposition.

The reason may well be climate change caused by increasing concentrations of atmospheric greenhouse gases — now roughly 390 parts per million, up from 280 ppm in the 1700s.

Current climate change is characterized by rising atmospheric carbon dioxide (CO2) concentrations and associated warming.

The work included data from a variety of sources, including national emissions inventories kept by the United Nations, global estimates of energy use and direct measurements of atmospheric CO2 concentrations, and involved dozens of authors from institutes around the world.

Receding Himalayan glaciers Almost six years ago, I was the editor of a single - topic issue on energy for Scientific American that included an article by Princeton University's Robert Socolow that set out a well - reasoned plan for how to keep atmospheric carbon dioxide concentrations below a planet - livable threshold of 560 ppm.

It concluded that atmospheric carbon dioxide concentrations had already increased by about 25 percent in the past century, and continued use of fossil fuels would lead to substantial temperature increases in the future.

It's correct that an extra methane molecule is something like 25 times more influential than an extra CO2 molecule, although that ratio is primarily determined by the background atmospheric concentration of either gas, and GWP typically assumes that forcing is linear in emission pulse, which is not valid for very large perturbations.

While ECS is the equilibrium global mean temperature change that eventually results from atmospheric CO2 doubling, the smaller TCR refers to the global mean temperature change that is realised at the time of CO2 doubling under an idealised scenario in which CO2 concentrations increase by 1 % yr — 1 (Cubasch et al., 2001; see also Section 8.6.2.1).

Continued use of fossil fuels into the 21st century is predicted to lead to atmospheric CO2 levels > 900 ppm by 2100 (under Representative Concentration Pathway (RCP) 8.5; Meinshausen et al., 2011), though the precise level is highly dependent on the emission scenario (Pachauri et al., 2014).

These rising atmospheric greenhouse gas concentrations have led to an increase in global average temperatures of ~ 0.2 °C decade — 1, much of which has been absorbed by the oceans, whilst the oceanic uptake of atmospheric CO2 has led to major changes in surface ocean pH (Levitus et al., 2000, 2005; Feely et al., 2008; Hoegh - Guldberg and Bruno, 2010; Mora et al., 2013; Roemmich et al., 2015).

So apparently you're suggesting that decadal - scale precipitation patterns (more, less rainfall) and temperature changes are better explained by atmospheric CO2 concentrations.

... The Earth's atmospheric methane concentration has increased by about 150 % since 1750, and it accounts for 20 % of the total radiative forcing from all of the long - lived and globally mixed greenhouse gases (these gases don't include water vapor which is by far the largest component of the greenhouse effect).

The Arctic Monitoring and Assessment Program (AMAP) carbon assessment published in 2009 highlighted the disparity in methane emissions estimated by extrapolating data from wetlands, lakes, and coastal waters underlain by permafrost (32 to 112 Tg CH4 yr - 1) and estimates based on spatial and temporal variability of atmospheric methane concentrations (15 to 50 Tg CH4 yr - 1).

For example, changes in Earth's atmospheric composition (especially the concentrations of greenhouse gases) may alter the climate, while climate change itself can change the atmospheric composition (for example by changing the rate at which weathering removes CO2).

The team's model predicted that foliage would increase by some 5 to 10 percent given the 14 percent increase in atmospheric CO 2 concentration during the study period.

Sea surface temperature change after doubling of atmospheric CO2 concentration in a scenario where CO2 increases by 1 % every year.

By this time, atmospheric CO2 concentration will probably have become sufficiently high (and we will be committed to further increases) that a climatic change significantly larger than any which has occurred in the past century could be unavoidable.»

This is a large effect for increasing the atmospheric carbon dioxide concentration by 100 ppm.

A new study by Carnegie's Ken Caldeira and Nathan Myhrvold of Intellectual Ventures concludes that about half of the warming occurs within the first 10 years after an instantaneous step increase in atmospheric CO2 concentration, but about one - quarter of the warming occurs more than a century after the step increase.

By trapping heat, rising concentrations of atmospheric pollution are causing glaciers and ice sheets to melt into seas, lifting high tides ever higher.

Once global carbon dioxide emissions had been reduced to zero, some combination of atmospheric decay and carbon dioxide extraction, probably partially offset by some level of carbon dioxide re-release from the worlds oceans, might possibly reduce the atmospheric carbon dioxide concentration to comply with the NAAQS.

Two different carbon dioxide (CO2) reduction scenarios are applied, both meeting an atmospheric CO2 concentration target of 450 ppm by the year 2100.

This is a large effect for increasing the atmospheric carbon dioxide concentration by 100 ppm.

By 2100, the ocean uptake rate of 5 Gt C yr - 1 is balanced by the terrestrial carbon source, and atmospheric CO2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models2, resulting in a global - mean warming of 5.5 K, as compared to 4 K without the carbon - cycle feedbacBy 2100, the ocean uptake rate of 5 Gt C yr - 1 is balanced by the terrestrial carbon source, and atmospheric CO2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models2, resulting in a global - mean warming of 5.5 K, as compared to 4 K without the carbon - cycle feedbacby the terrestrial carbon source, and atmospheric CO2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models2, resulting in a global - mean warming of 5.5 K, as compared to 4 K without the carbon - cycle feedback.

One could quibble with the use of the high - energy UV (which never penetrates to the lower troposphere), and the high concentrations of SO2 and O3, but by far the biggest problems lie in the study's relevance to the real world atmospheric conditions.

The largest contribution to total radiative forcing is caused by the increase in the atmospheric concentration of CO2 since 1750.

In doing so, we have limited our considerations to the direct climatic effects of steadily rising atmospheric concentrations of CO2 and have assumed a rate of CO2 increase that would lead to a doubling of airborne concentrations by some time in the first half of the twenty - first century.

Oeschger and his colleagues in Bern were the first to measure the glacial - interglacial change of atmospheric CO2 in ice cores, showing that atmospheric concentrations of CO2 during the glacial period was 50 % lower than the pre-industrial concentration, a result predicted by Arrhenius nearly a century earlier.

This implies that most CO2 is removed from the atmosphere within about 4 years, but it isn't, it is mostly just replaced by CO2 from natural sources, which doesn't change atmospheric concentrations.

My understanding is the world has had reduced emissions since 2014, but it hasn't shown up in the keeling curve atmospheric concentrations because its been obscured by the big 2015 el nino generating a lot of CO2 related to forests etc..