Sentences with phrase «say global concentrations»

Carbon levels fluctuate depending on the region and the season and scientists say global concentrations will likely remain at around 395 ppm for the time being.

Not exact matches

A joint statement from the National Academy of Sciences and Royal Society in Britain said «human - induced increases in CO2 (carbon dioxide) concentrations have been the dominant influence on the long - term global surface temperature increase.»

That said, slumping global rig activity, especially in offshore drilling where NOW has a heavy customer concentration, more than overcame the boost the company received from acquisitions.

The draft report by the U.S. Global Change Research Program says it is likely the world will forfeit its ability to meet «rapid emission reduction» scenarios needed to stabilize greenhouse gas concentrations «within a few years.»

The government's attorneys said in court papers last month that the concentration of 350 ppm of CO2 isn't necessarily dangerous but acknowledged the country bears significant responsibility for fueling global warming (Climatewire, Jan. 18).

To achieve 450 ppm, the concentration of greenhouse gases in the atmosphere associated with a 2 - degree Celsius rise in global average temperatures (a target advocated by the European Union), the «aggregate of fossil - fuel demand will peak out in 2020,» Tanaka says.

«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 draft report says that a doubling of the preindustrial concentration of carbon dioxide in the atmosphere is likely to reduce global GDP by between 1 and 3 per cent by the middle of the next century.

If global levels of hydroxyl decrease, global methane concentrations will increase — even if methane emissions remain constant, the researchers say.

«This underscores that large, sustained changes in global temperature like those observed over the last century require drivers such as increased greenhouse gas concentrations,» said lead author Patrick Brown, a PhD student at Duke's Nicholas School of the Environment.

Climate scientists say politicians must move on from Kyoto - style piecemeal negotiations on individual national targets to a global plan to cap concentrations of critical greenhouse gases, especially CO2.

«I agree that carbon dioxide is a greenhouse gas, that greenhouse gas concentrations in the atmosphere are increasing as a result of human activities — primarily burning coal, oil, and natural gas — and that this means the global mean temperature is likely to rise,» Ebell said in the statement released by CEI yesterday.

«Global climate change involves not just a warming planet, but also increased atmospheric CO2 concentrations and changes in rainfall,» said lead author Lauren Smith - Ramesh, a postdoctoral fellow at NIMBioS.

«It is ironic that high concentrations of molecules with high global warming potential (GWP), the worst - case scenario for Earth's climate, is the optimal scenario for detecting an alien civilization, as GWP increases with stronger infrared absorption and longer atmospheric lifetime,» say the authors.

«The increased use of clean energy sources that do not emit greenhouse gases or conventional air pollutants... would be doubly beneficial to global food security, as they do not contribute to either climate change or increased surface - ozone concentrations,» she said.

«Atmospheric CO2 concentrations have been remarkably stable over the last 20 or 25 million years despite other changes in the environment,» says co-author Ken Caldeira of the Carnegie Institution's Department of Global Ecology.

«This will cause carbon loss from the soil which means an increase in carbon dioxide concentration in the atmosphere, which will further worsen global warming,» said Takeshi Ise from the Japan Agency for Marine - Earth Science and Technology.

Yet to say that «Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations», science must «very likely» know everything important about the subject.

However, if the CO2 ppm were extended back to say 1905, the graph would show a strong disconnect between the rise of the CO2 concentration and the global temperature between 1905 and 1945.

Lawrence Cathles at Cornell said he had confidence that more observation, from direct measurements to global tracking of methane concentrations, would allow gas development to proceed while limiting climate impacts.

«This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120ppm since pre-industrial times,» Pieter Tans, lead scientist of NOAA's greenhouse gas network, said in an interview to The Guardian Wednesday.

Mr. Clinton says his goal is to reduce the threat in coming decades of droughts, coastal floods, and famine from global warming — a warming of the atmosphere caused by rising concentrations of gases, especially carbon dioxide, released when fuels and forests are burned.

So the 3.7 W m - 2 calculation for global radiative forcing could be refined perhaps by an improved experimental design (not necessarily by improved radiative transfer models) running RT models at each grid cell over the globe, over the diurnal cycle and the annual cycle for say 30 years, for the two different CO2 concentrations, such a detailed calculation would refine the 3.7 value.

There are plenty, but for a conservative example see IPCC Synthesis Report 2007 Table 5.1 which says to stay within 2 - 2.4 degrees global average temperature increase above pre-industrial (Copenhagen upper «low risk» target) and 425 - 490ppm CO2 - equivalent concentration at stabilisation, the required change in global CO2 emissions in 2050 (percent of 2000 emissions) is decline between 85 to 50 percent.

1700: A new study aims to highlight the potential of a geoengineering technique referred to as «marine cloud - brightening» (MCB) which researchers say has the potential to cancel out the effects of global warming in a world double the CO2 concentration of the pre-industrial world.

says that increasing the concentration of CO2 in the atmosphere should increase the strength of this alleged greenhouse effect, and thereby cause «global warming».

Judith said:» The key argument in their paper is that an increase in coal burning (primarily in China) has increased atmospheric sulfate concentration with a resulting global cooling effect.»

In a sharp change from its cautious approach in the past, the National Academy of Sciences on Wednesday called for taxes on carbon emissions, a cap - and - trade program for such emissions or some other strong action to curb runaway global warming.Such actions, which would increase the cost of using coal and petroleum — at least in the immediate future — are necessary because «climate change is occurring, the Earth is warming... concentrations of carbon dioxide are increasing, and there are very clear fingerprints that link [those effects] to humans,» said Pamela A. Matson of Stanford University, who chaired one of five panels organized by the academy at the request of Congress to look at the science of climate change and how the nation should respond.

You said here that carbon concentrations will peak at 400 ppm in 2025 under the ideal situation, but it's only 2015 and we're already at 400 ppm, and I see no signs of global emission reductions happening soon.

As the Report says: «there is high confidence (medium evidence and high agreement) that the GCR - ionization mechanism is too weak to influence global concentrations of cloud condensation nuclei or their change over the last century or during a SC in a climatically - significant way»

The Lewis and Curry paper said the best estimate for equilibrium climate sensitivity — the change in global mean surface temperature at equilibrium that is caused by a doubling of the atmospheric CO2 concentration — was 1.64 degrees.

It is often said that the greenhouse effect and man - made global warming theories are «simple physics», and that increasing the concentration of carbon dioxide in the atmosphere must cause global warming.

He says low values of climate sensitivity will still affect global temperatures as CO2 concentrations in the atmosphere rise, but increases in temperature may be of similar magnitude to naturally driven temperature cycles, a scenario that has strong implications for how we manage causes and consequences of climate change.

«Whilst there are certainly other potential drivers of changes in the climate we know that over the last century we have greatly increased the CO2 concentration in the atmosphere and, through detection and attribution analyses, we know that the rising levels of atmospheric CO2 and other greenhouse gases have driven the rise in global temperature,» King said.

GENEVA - Global warming gases have hit record levels in the world's atmosphere, with concentrations of carbon dioxide up 39 per cent since the start of the industrial era in 1750, the U.N. weather agency said Monday.

Among its findings, the assessment said that increased concentrations of greenhouse gases in the atmosphere would «contribute to additional Arctic warming of about 4 - 7C (7 - 13F), about twice the global average, over the next 100 years».

The lack of a «conceivable pathway to reducing CO2 concentrations... on the timescales put forth by the Paris Agreement» is not improved by said Agreement's permitting «developing countries» (responsible for about 65 % of global emissions) to prioritise «economic... development and poverty eradication» over CO2 reduction, merely encouraging them to «move over time towards... emission reduction or limitation targets»: https://judithcurry.com/2016/08/16/cop21-developing-countries/

It's said by suspected fossil fuel lobbyists and the idiots Trump has appointed to oversee environmental agencies that «scientists don't agree» over global warming, actually the problem is that the results don't agree, inasmuch as the graphs tend to be polynomial — also it's quite difficult to measure methane concentrations, it appears, as they vary considerably according to altitude.

While applauding Mr. Gore's enthusiasm, many energy experts said this stance was counterproductive because there was no way, given global growth in energy demand, that existing technology could avert a doubling or more of atmospheric concentrations of carbon dioxide in this century.

That is to say, they show that increasing CO2 concentration in the air does cause global warming.

I think that in your penultimate sentence you meant to say that «increasing CO2 concentration in the air does not cause global warming.»

Levels of greenhouse gases such as carbon dioxide and nitrous oxide continue to climb, the report authors say; atmospheric CO2 concentrations reached a global average of 397.2 ppm last year, compared with the average of 354.0 in 1990, the first year the annual State of the Climate report was issued.

The IPCC says (in the AR5 SPM), «It is extremely likely [defined as 95 - 100 % certainty] that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic [human - caused] increase in greenhouse gas concentrations and other anthropogenic forcings together.»

More importantly, you say: «First off, they (climate scientists) certainly do have the most expertise when it comes to «what is the likely impact of a given emission policy on CO2 concentrations and global mean temperature»?

RealClimate is wonderful, and an excellent source of reliable information.As I've said before, methane is an extremely dangerous component to global warming.Comment # 20 is correct.There is a sharp melting point to frozen methane.A huge increase in the release of methane could happen within the next 50 years.At what point in the Earth's temperature rise and the rise of co2 would a huge methane melt occur?No one has answered that definitive issue.If I ask you all at what point would huge amounts of extra methane start melting, i.e at what temperature rise of the ocean near the Artic methane ice deposits would the methane melt, or at what point in the rise of co2 concentrations in the atmosphere would the methane melt, I believe that no one could currently tell me the actual answer as to where the sharp melting point exists.Of course, once that tipping point has been reached, and billions of tons of methane outgass from what had been locked stores of methane, locked away for an eternity, it is exactly the same as the burning of stored fossil fuels which have been stored for an eternity as well.And even though methane does not have as long a life as co2, while it is around in the air it can cause other tipping points, i.e. permafrost melting, to arrive much sooner.I will reiterate what I've said before on this and other sites.Methane is a hugely underreported, underestimated risk.How about RealClimate attempts to model exactly what would happen to other tipping points, such as the melting permafrost, if indeed a huge increase in the melting of the methal hydrate ice WERE to occur within the next 50 years.My amateur guess is that the huge, albeit temporary, increase in methane over even three or four decades might push other relevent tipping points to arrive much, much, sooner than they normally would, thereby vastly incresing negative feedback mechanisms.We KNOW that quick, huge, changes occured in the Earth's climate in the past.See other relevent posts in the past from Realclimate.Climate often does not change slowly, but undergoes huge, quick, changes periodically, due to negative feedbacks accumulating, and tipping the climate to a quick change.Why should the danger from huge potential methane releases be vievwed with any less trepidation?

«On our current path, we will find it extremely difficult to rein in carbon emissions enough to stabilise the atmospheric CO2 concentration at 450 parts per million and even 550 ppm will be a challenge,» says Josep Canadell, executive director of the Global Carbon Project.

As Judith says, one of the key conclusions is the paragraph in large red letters «Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations... Discernible human influences now extend to other aspects of climate, including ocean warming, continental - average temperatures, temperature extremes and wind patterns (see Figure SPM.4 and Table SPM.2).»

I can't find the context of the text fragment used as an example of the «minimizes» subset of Level 6 in Table 2 but the most likely reading of the fragment by itself is that it assumes that humans are causing atmospheric greenhouse gas concentrations to increase and that this is causing or contributing to global warming, so the fragment does say (or at least imply) something about human attribution.

While it was true that the atmospheric concentration of carbon dioxide had been increasing, he said, and had passed 400 parts per million, the dominant effect of water vapor had helped flatten the greenhouse effect, such that the rise of global surface temperatures had slowed significantly.