Future: to 2050

Extreme Heat - the Insurance Fallouts 0625.rtf

     Projected global surface temperature changes under zero CO2 emissions (blue line), zero CO2 and aerosol emissions (red), zero GHG emissions (yellow) and zero GHG and aerosol emissions (purple). Chart by Carbon Brief using Highcharts, adapted from Figure 1.5 in the IPCC SR15.

     Historical warming values (black) and combination with model simulations are estimated using the methods described in the first figure.

Albedo Effect of Retreating Arctic Sea Ice - Hudson 0811.pdf

    Albedo warming effect of complete Arctic Ocean ice loss is ~1/4 of the rise since 1750 from added GHGs.  ~15% of that ice albedo warming effect has already occurred.

Below is context for understanding projections of future warming.

     Representative Concentration Pathways (RCPs) are needed to interpret the graphs below it.  RCPs are newer scenarios than the IPCC used in 2007 (A2, B1, etc.)

     Caveat: these appear not to include positive feedback loops, especially carbon emissions from thawing permafrost.

The figure shows fossil fuel carbon emission pathways for the CO2e levels above: IPCC 5 Fig. TS-19.

    The inset graph relates RCP emission paths to ppm CO2 in the air.

     Four RCP emission paths are shown: in billion tonnes (Pg) of carbon per year.
    In RCP 2.6, net world CO2 emissions from fossil fuels peak ~2020, at ~10% higher than today's.  They fall below zero ~2075.  In this case, CO2 levels peak at ~450 ppm and fall to ~420 by 2100.  Relative to 1901-60, the US has already warmed 2°F.  We will warm 2°F more by ~2045, levelling off thereafter.
    In RCP 4.5, emissions peak ~2040, at 130% of today's, then fall to 60% of today's in 2080.  CO2 levels rise to ~540 ppm.  The US warms 4°F more by 2100.

Extreme Heat Will Change Us 1222.rtf - health, adaptation, inequality, the future - The story compares laborers and other people in Kuwait and Basra, Iraq.  Kuwaiti citizens (but not laborers).  Most Kuwaitis avoid going outside.  Air conditioning is a rare luxury in Basra (Garden of Eden land), where it got to 164°F on the welder's benchtop and 179°F on a tire swing on a playground.  The struggle to sweat and cool off increases risk of kidney stones and kidney disease.  The welder's body temperature rose 3°C, a dangerous fever, from the outdoor heat.  Chronic dehydration abounds in Basra.

Will Global Warming ‘Stop’ as Soon as Net-Zero Emissions Are Reached? 0421.rtf

"The best available evidence shows that, on the contrary, warming is likely to more or less stop, once carbon dioxide (CO2) emissions reach zero."  This is incorrect.  Hausfather (the article's author) says, once emissions reach net-zero, temperatures were expected to remain steady, rather than dropping for a few centuries after emissions reach zero.  A NASA climate FAQ – last updated in 2007 – says that “even if we stopped emitting GHGs today, global warming would continue to happen for at least several more decades, if not centuries”.
    Natural processes will remove CO2 from the air.  Rock weathering will do so about 2% as fast as we we are adding CO2 to the air.  But there is far more CO2 in the air from our 2 centuries of legacy emissions.  At that rate, rock weathering would take 1-2 millennia to remove most of the legacy emissions.
    However, the oceans and biosphere now absorb about half of human emissions each year.  If the oceans keeps absorbing CO2 at the current rate, oceans will remove CO2 from the air faster than rock weathering does.
    However, the oceans are unlikely to keep absorbing CO2 at roughly the present rate, or much at all, since they are aleady very close to CO2 equilibrium with the atmosphere.  As Prof. Klaus Lackner (a pioneer in CO2 removal) explains, "If CO2 in the air does not rise, the rate of uptake by the ocean and the biomass both slow down dramatically.  As long as the CO2 in the air goes up, the CO2 goes fast into the ocean.  The atmosphere is about a year or two ahead of the mixed layer.  If the CO2 in the air does not go up, the only way the mixed layer takes more is that it sheds CO2 to the next layer below.  The longer you leave it that way, the slower this transport will be.  It is roughly proportional to the gradient.  The deeper the CO2 gets, the shallower this gradient will be.  If emissions were to stop, it is the deeper ocean which has to pick up CO2 and the smaller the gradient, the slower it gets.   The net result is that the uptake goes down rapidly.  As a result, it will take the ocean more than 1,000 years to get in equilibrium with the air.  And even then, the last 20% stays."

     From another perspctive, the paleoclimate record is pretty clear that today's CO2 levels are associated with planetary surface warming of 2.5-5°C hotter than now, once changed ocean circulation from the joining of North and South America 3 million years ago is accounted for.

Albedo Changes Drive 4.9 to 9.4°C Global Warming by 2400.pdf - 15pp Fry 1220

Dr. Fry’s Research, in graphs

Dr. Fry's scenarios show faster warming than most other scenarios, mostly because they are driven by albedo changes, which were triggered by more CO2 and methane.

The scenarios and results are by Dr. Fry, whose website this is.

Below are graphs by Dr. James Hansen

Climate Change Will Expose Millions of Americans to ‘Off the Charts’ Heat 0719.rtf - take 4 on study

Earth Facing ‘Global Warming Armageddon’ in Less than 150 Years 0219.rtf 5-8°C warming, like 55 million years ago.  Below are scenarios that badly underestimate future changes from albedo effects, from the IPCC in October 2018.

Immediate Fossil Fuel Phaseout Could Arrest Climate Change 0119.rtf -

     It would not slow climate change very much, until the amplifying feedbacks we have unleashed play out.  But it would prevent 2 to 3°C warming that otherwise would occur by about 2400 if we waited till 2050 to phase out fossil fuels entirely.  That would mean the difference between continued civilization and deep (80-90%) cuts in human population.   Of course, waiting longer to phase out fossil fuel use would make future warming even worse, threatening actual extinction of humans.

Earth at Risk of Becoming ‘Hothouse' if Tipping Point Is Reached 0818.rtf

    Amplifying feedbacks mentioned include permafrost thaw; loss of seabed methane hydrates; weaker land and ocean carbon sinks, starting with forest dieback and increased bacteria respiration; loss of Arctic summer sea ice; reduced Antarctic sea ice; and loss of polar ice sheets.
    “To reverse the potential domino effect … requires … improved forest, agricultural and soil management; biodiversity conservation; and technologies that remove CO2 from the atmosphere and store it underground....  More broadly,  'collective human action' is required to steer us a way from this potential threshold: 'decarbonization of the global economy, enhancement of biosphere carbon sinks’ ….

     The report projects that tipping point elements will happen at differing global temperatures.

NASA’s Tons of Data Help Developing Nations Prepare for Global Warming 0615.rtf - 

below, 45°C = 113°F.

RCP 8.5 (see 2 maps below) is the highest human emissions case; it may include a bit of permafrost carbon emissions.
    The Indian Ocean surface is mostly 80°F in this projection, but pockets of 90-100°F water surround Indonesia and Malaya.  Seas around Siciy and Greece also hit 90°F.  The Red Sea surface reaches 110°F.  Normal temperatures reach 100°F in much of the US and eastern China.

Climate Change Will Hit Australia Harder Than Rest of the World 0115.rtf

Heat in the Heartland - Climate Change and Economic Risk in the Midwest - Risky Business / Grayson 0115.pdf - 58 pp

    Days above 95°F will roughly triple. This includes 75-100 such days a year for southern Illinois (Carbondale, Cairo, Vincennes, plus Decauter) and more than half of Missouri (St. Louis, Cape Girardeau, Joplin, Sedalia, Rolla, Poplar Bluff, Hannibal, etc.)  It also includes Evansville IN, plus slivers of Ohio between Portsmouth and Marietta and Iowa north of Hannibal.  75-100 days a year above 95°F is almost as hot as Las Vegas (99-114, 2012-14).
    The Midwest in particular will experience rising temperatures, in terms of warmer winters more than unbearable summers. But by the end of the century, the average Midwesterner will likely see 22 to 77 days per year over 95°F, compared to only 3, on average, over the past 30 years. 

     There is a 5% (or more) chance that 125-150 days a year will exceed 95°F in much the same area (plus Terre Haute and Jasper IN and Effingham IL, but minus Hannibal and Sedalia MO).  See the rest of Figure 1 in the report for the 5% tail.

     These compare to 114 days above 95°F for Las Vegas in 2014, 95 such days in 2013, and 115 in 2012.  The southern Midwest can become hotter than Las Vegas by the end of the century (or a little later), if current emission trends continue.

Heat Stroke Index (Wet Bulb Temperatures)

Heat in the Heartland Midwest Agriculture & Climate Risks.pdf - a piece of the above study.  Highlights are below.

     Agriculture will be harmed in a major way.  Crop losses of 40-64% by 2100 are likely for corn in the Corn Belt and 8-38% by 2100 for soybeans in the same states (IA, IL, IN, OH, MO).  The Corn Belt will have moved into Canada, North Dakota, and NW Minnesota.  See maps and table below.  In most of Missouri and Illinois, plus about half of Iowa and Indiana, crops losses are 25-50%, and worse in a few places.  Wheat is much less affected, as it is often grown in the colder months and harvested by June.

Earth, 2300 - Too Hot for Humans 0510.rtf

     Projected regional wet-bulb temperatures for an average global temperature increase of 12°C.
Human cannot survive wet-bulb temepratures over 35°C. (Image from Steven C. Sherwood / Matthew Huberb)
    Most of the eastern US, India, Australia, the Middle East, and central South America become uninhabitable.  Also Spain, China from Shanghai to Tianjin, Egypt, and west Africa.

from 2013 draft US National Climate Assessment (& Overviews page - see RCP paths there)

World Warming: from IPCC's 2007 Science Summary.  1°C (below) = 1.8°F (above).  Projected warming is faster in the US than the world as a whole.  Relative warming increases toward the poles (see below).  Observed warming was 0.2°C in 2000, relative to baseline.

World Warming by Location: from IPCC's 2013 Science Summary.

     The 2 maps below are similar, but not identical, to the draft US National Climate Assessment's maps on the Overviews page.  RCPs are summarized on the Overviews page.

     Temperature rise is greater toward the poles and over land.

     Dotted areas indicate high agreement among models.

   4°C surface warming worldwide translates to 10°F warming averaged across the US.  6-7°F in Florida, 7-8°F in the Southeast and coastal California, but 11°F in Iowa, Minnesota, the Dakotas, and Utah/Idaho.  Also 13°F over much of Alaska.

Section Map: Heat