Soil moisture 12 inches below ground projected through 2100 for
a high greenhouse gas emissions scenario.
We analyzed the effect of a medium -
high greenhouse gas emissions scenario (Special Report on Emissions Scenarios A2 in IPCC 2000) and included updated projections of sea - level rise based on work by Rahmstorf (Science 315 (5810): 368, 2007).
She and her team then projected excess deaths from heat under a low and
a high greenhouse gas emissions scenario, incorporating adaptation patterns.
Under both modest and
high greenhouse gas emissions scenarios, temperatures in the Colorado River Basin are projected to rise by 5 degrees Fahrenheit compared with the 20th - century average.
Not exact matches
Headed toward an 8 F rise in warming Other such low - probability but
high - risk
scenarios mentioned in the report include ecosystem collapses, destabilization of methane stored in the seafloor and rapid
greenhouse gas emissions from thawing Arctic permafrost.
The researchers find that «ocean - driven melt is an important driver of Antarctic ice shelf retreat where warm water is in contact with shelves, but in
high greenhouse -
gas emissions scenarios, atmospheric warming soon overtakes the ocean as the dominant driver of Antarctic ice loss.»
They looked at each of those conditions through, first, a business - as - usual lens that assumes a lack of international climate - policy action with continued
high rates of
greenhouse gas emissions and, second, an optimistic
scenario of reduced
emissions with climate change policy interventions.
The researchers analyzed climate suitability projections over time for 513 species across 274 national parks, under a
high and low
greenhouse gas emission scenario.
Global rates of temperature change in
high and declining
greenhouse gas emission scenarios.
These results and the emerging additional regions of
highest climate change vulnerability under
high emissions scenarios (Figures S7, S8, S9) suggest that global policies that mitigate
greenhouse gas emissions will substantially reduce species» climate change vulnerability.
If nations continue to increase their
emissions of
greenhouse gases in a «business - as - usual»
scenario, the U.S. ratio of daily record
high to record low temperatures would increase to about 20 to 1 by midcentury and 50 to 1 by 2100.
The area of near - surface permafrost in the Northern Hemisphere is projected to decline by 20 % relative to today's area by 2040, and could be reduced by as much as two - thirds by 2080 under a
scenario of
high greenhouse gas emissions.
When talking to the media, some have been tempted to push beyond what the science supports — focusing on the
high end of projections of global temperatures in 2100 or highlighting the scarier
scenarios for
emissions of
greenhouse gases.
In our study we also showed that, while difference between
high and low immigration
scenarios is 70 Mt of
greenhouse gas emissions in Australia's by 2020, the world's
greenhouse gas emissions would increase by less than half of this amount since immigrants to Australia come from countries that have per capita
emissions levels less than half of Australia's (around 42 %).
It cited «plausible
scenarios in which GHG [
greenhouse gas]
emissions from corn - grain ethanol are much
higher than those of petroleum - based fuels,» and questioned the method by which EPA determined that ethanol would produce 21 percent less
emissions.
The energy system reference cases used for future
greenhouse gas (GHG)
emission pathways in climate change research are a case in point: baseline
emission scenarios commonly project levels of coal combustion many times
higher than current reserve estimates by the year 2100.
The modeling results indicate that, if nations continue to increase their
emissions of
greenhouse gases in a «business as usual»
scenario, the U.S. ratio of daily record
high to record low temperatures would increase to about 20 - to - 1 by mid-century and 50 - to - 1 by 2100.
However, the model results are important because they show that, in all likely
scenarios of future
greenhouse gas emissions, record daily
highs should increasingly outpace record lows over time.
Lam and team used climate models from the Intergovernmental Panel on Climate Change to examine the economic impacts of climate change on fish stocks and fisheries revenues under two different
emissions scenarios: a
high -
emission scenario, in which the rates at which
greenhouse gases are pumped into the Earth's atmosphere continue to rise unchecked, and a low -
emission scenario under which ocean warming is kept below two degrees Celsius.
RCP8.5 is a
scenario of «comparatively
high greenhouse gas emissions «brought about by rapid population growth,
high energy demand, fossil fuel dominance and an absence of climate change policies.
The radiative forcing estimates are based on the forcing of
greenhouse gases and other forcing agents.5 The four selected RCPs were considered to be representative of the literature, and included one mitigation
scenario leading to a very low forcing level (RCP2.6), two medium stabilization
scenarios (RCP4.5 / RCP6) and one very
high baseline
emission scenarios (RCP8.5).
Both wetland drying and the increased frequency of warm dry summers and associated thunderstorms have led to more large fires in the last ten years than in any decade since record - keeping began in the 1940s.9 In Alaskan tundra, which was too cold and wet to support extensive fires for approximately the last 5,000 years, 105 a single large fire in 2007 released as much carbon to the atmosphere as had been absorbed by the entire circumpolar Arctic tundra during the previous quarter - century.106 Even if climate warming were curtailed by reducing heat - trapping
gas (also known as
greenhouse gas)
emissions (as in the B1
scenario), the annual area burned in Alaska is projected to double by mid-century and to triple by the end of the century, 107 thus fostering increased
emissions of heat - trapping
gases,
higher temperatures, and increased fires.
While these uncertainties prevent the establishment of a
high - confidence, one - to - one linkage between atmospheric
greenhouse gas concentrations and global mean temperature increase, probabilistic analyses can assign a subjective probability of exceeding certain temperature thresholds for given
emissions scenarios or concentration targets (e.g., Meinshausen, 2005; Harvey, 2007).
A few years ago Hal Turton and I modeled the effect of
high versus low immigration
scenarios on expected growth of Australia's
greenhouse gas emissions.
Researchers for the first time have calculated the
highest tolerable «wet - bulb» temperature and found that this temperature could be exceeded for the first time in human history in future climate
scenarios if
greenhouse gas emissions continue unabated.
«With a
high scenario for future
greenhouse gas emissions, the largest warming occurs over the
high latitudes of the Northern Hemisphere, but all land areas warm dramatically,» remarked Field
The rate of increase depends on whether global
greenhouse gases follow a low or
high emission scenario.