Since human emissions can be calculated in actual tonnage, simple algebra can show the relative contributions of CO2 to
the atmospheric concentration from human and other sources.
The natural fluxes can be split to a reaction to the deviation of
the atmospheric concentration from a value that would be in balance with the other Earth systems in absence on any other net fluxes and to the other natural fluxes that are independent of the present concentration.
We know that additional GHGs can not be the cause as there was no discernible increase in
the atmospheric concentration from the the pre-industrial period.
As a result, this paper asserts that to prevent dangerous climate change the world must not only reduce its emissions but reduce existing greenhouse gas CO2
atmospheric concentrations from the current 394 ppm to 350 ppm CO2 to avoid dangerous climate change.
Not exact matches
The most detailed measurements currently available of
atmospheric methane
concentrations come
from a sensor aboard the European Space Agency's Sentinel - 5P spacecraft, which launched in October 2017 (ref.
To see if these regulations affected bromine
concentrations,
atmospheric chemist Stephen Montzka of the National Oceanic and
Atmospheric Administration in Boulder, Colorado, and colleagues analyzed air samples taken several times each month
from 10 land - based sites across the globe between 1995 and 2002.
Growth rates for
concentrations of carbon dioxide have been faster in the past 10 years than over any 10 - year period since continuous
atmospheric monitoring began in the 1950s, with
concentrations now roughly 35 percent above preindustrial levels (which can be determined
from air bubbles trapped in ice cores).
Keeping
atmospheric concentrations of greenhouse gases below 550 ppm, let alone going back to 350 ppm or below, will not only require a massive shift in human society —
from industry to diet — but also, most likely, new technologies, such as capturing CO2 directly
from the air.
About half of this near - term warming represents a «commitment» to future climate change arising
from the inertia of the climate system response to current
atmospheric concentrations of greenhouse gases.
Even though the information of the exact species present in the monitored area and pollen release patterns of the individual species are far
from complete, Peel and his colleagues conclude that the best way to explain the three
concentration patterns is to look at the succession of different grass species with different diurnal flowering patterns which dominate the
atmospheric pollen loads as the season progresses.
In India, a broad increase in fertilizer use coupled with large contributions
from livestock waste have resulted in the world's highest
concentrations of
atmospheric ammonia.
To get a global look at methane
concentrations before, during, and after the plateau, the team amassed
atmospheric methane
concentration data
from measuring stations
from Canada to China to Australia, spanning a period
from 1984 through 2015.
Photosynthesis — the process green plants use to convert energy
from the sun that plants use to grow —
from tropical forests, plays a huge role in determining global
atmospheric CO2
concentration, which is closely linked the global temperature and rate of climate change.
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.
Tropospheric ozone — a greenhouse gas and the kind that affects the air we breathe — can increase in
concentration because of
atmospheric conditions, or can result
from human activities.
«This relationship between Antarctica temperature and CO2 suggested that somehow the Southern Ocean was pivotal in controlling natural
atmospheric CO2
concentrations,» said Dr Maxim Nikurashin
from the ARC Centre of Excellence for Climate System Science.
Elevated mercury emissions also coincided with previously established increases in
atmospheric CO2
concentrations, indicating CO2 release
from volcanic degassing.
To verify emissions
from the San Juan and Four Corners coal - fired power plants, the Los Alamos team deployed ground - based solar spectrometers and point sensors to measure
atmospheric concentrations of gases at a site close to these power plants.
[NASA's OCO - 2 Mission in Pictures (Gallery)-RSB- The
concentration of
atmospheric carbon dioxide — a heat - trapping «greenhouse gas» — has risen
from 280 parts per million (ppm) before the Industrial Revolution to about 400 ppm today.
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.
Patrick Crill, an American biogeochemist at Stockholm University, says ice core data
from the past 800,000 years, covering about eight glacial and interglacial cycles, show
atmospheric methane
concentrations between 350 and 800 parts per billion in glacial and interglacial periods, respectively.
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.
Within that range of
atmospheric density, even higher
concentrations of carbon dioxide wouldn't have been adequate to counteract the faint young sun, suggesting that methane, ethane or other strong greenhouse gases kept Earth
from freezing.
«During photosynthesis plants bind
atmospheric carbon, whose isotopic composition is preserved in resins over millions of years, and
from this, we can infer
atmospheric oxygen
concentrations,» explains Ralf Tappert.
A recent trend in GCMs is to extend them to become Earth system models, that include such things as submodels for
atmospheric chemistry or a carbon cycle model to better predict changes in carbon dioxide
concentrations resulting
from changes in emissions.
«(A) describe increased risks to natural systems and society that would result
from an increase in global average temperature 3.6 degrees Fahrenheit (2 degrees Celsius) above the pre-industrial average or an increase in
atmospheric greenhouse gas
concentrations above 450 parts per million carbon dioxide equivalent; and
The effects of increased temperatures and
atmospheric CO2
concentration have been documented concerning shifts in flowering time and pollen initiation
from allergenic plants, elevated production of plant - based allergens, and health effects of increased pollen
concentrations and longer pollen seasons.15, 16,17,18,19,20,21,22,23,24,25,26 Additional studies have shown extreme rainfall and higher temperatures can lead to increased indoor air quality issues such as fungi and mold health concerns.27, 28,29,30
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).
Previous recipients of the prize include the godfather of climate modelling, Syukuro Manabe,
from the US National Oceanic and
Atmospheric Administration's Geophysical Fluid Dynamics Laboratory, Norway's former Prime Minister Gro Harlem Brundtland, and Charles Keeling
from the University of California at San Diego who gave his name to the famous Keeling curve of
atmospheric CO2
concentration measurements.
Since each of the infrared - absorbing
atmospheric gases has its own unique absorption spectrum, the total infrared absorption capacity of the atmosphere is then due to the real - time
concentration and distribution of all the gases in the atmosphere,
from the surface to the stratosphere.
Variations of deuterium (δD; black), a proxy for local temperature, and the
atmospheric concentrations of the greenhouse gases CO2 (red), CH4 (blue), and nitrous oxide (N2O; green) derived
from air trapped within ice cores
from Antarctica and
from recent
atmospheric measurements (Petit et al., 1999; Indermühle et al., 2000; EPICA community members, 2004; Spahni et al., 2005; Siegenthaler et al., 2005a, b).
The
concentration of
atmospheric CO2 has increased dramatically since the Industrial Revolution (
from around 280 parts per million [ppm] in preindustrial times to 401 ppm in 2015), primarily due to human activities such as the burning of fossil fuels and changes in land - use.
Changes in important global
atmospheric greenhouse gas
concentrations from year 0 to 2005 AD (ppm, ppb = parts per million and parts per billion, respectively)(Forster et al. 2007).
One would see the temperature line rising away
from the SOI line if, for example, rising
atmospheric carbon dioxide
concentrations had a significant influence.
... 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).
One recent study examining the Palaeocene — Eocene Thermal Maximum (about 55 million years ago), during which the planet warmed 5 - 9 °C, found that «At accepted values for the climate sensitivity to a doubling of the
atmospheric CO2
concentration, this rise in CO2 can explain only between 1 and 3.5 °C of the warming inferred
from proxy records» (Zeebe 2009).
If we continue increasing
atmospheric CO2
concentrations with emissions
from the burning of coal, oil, and gas, the Earth will continue to get hotter.
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.
That is the case whether you are extrapolating
from paleoclimate data or
from any recent temperature dataset vs
atmospheric CO2
concentration measurements (eg Keeling curve).
• The methanetrack.org website has shown significant increases in
atmospheric methane
concentrations over Antarctica this austral winter (which I believe are due to increases in methane emissions
from the Southern Ocean seafloor due to increases in the temperature of bottom water temperatures), and if this trend continues, then the Southern Hemisphere could be a significant source of additional
atmospheric methane (this century).
AR4 WG1 at Table 7.1 admits they exist, but as they have NEVER been measured, of necessity reports them as a residual (
from Emissions minus change in
atmospheric CO2
concentration).
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.
If emissions did plateau, the
atmospheric concentrations would continue to rise at a steady rate but with just 2 % (compound) difference
from the rises of recent decades.
If the surface ocean pCO2
concentrations continue to increase in proportion with the
atmospheric CO2 increase, a doubling of
atmospheric CO2
from preindustrial levels will result in a 30 % decrease in carbonate ion
concentration and a 60 % increase in hydrogen ion
concentration.
Keeling, Piper and Heimann (1996), Global and hemispheric CO2 sinks deduced
from changes in
atmospheric O2
concentration, Nature, Vol 381, 218 - 221.
It is found that a radiative forcing
from non-CO2 gases of approximately 0.6 W m -LRB--2) results in a near balance of CO2 emissions
from the terrestrial biosphere and uptake of CO2 by the oceans, resulting in near - constant
atmospheric CO2
concentrations for at least a century after emissions are eliminated.»
The response of the internal variability of the Atlantic Meridional Overturning Circulation (MOC) to enhanced
atmospheric greenhouse gas
concentrations has been estimated
from an ensemble of climate change scenario runs.
This was a relatively stable climate (for several thousand years, 20,000 years ago), and a period where we have reasonable estimates of the radiative forcing (albedo changes
from ice sheets and vegetation changes, greenhouse gas
concentrations (derived
from ice cores) and an increase in the
atmospheric dust load) and temperature changes.