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Scientists believe 100% of global warming is due to humans

PostPosted: 14 Dec 2017, 12:17
by Squire
By the year 2100 the average land temperature will be 3 degrees C higher than now.

Below is an interesting article explaining why humans are responsible for 100% of global warming.

https://www.carbonbrief.org/analysis-why-scientists-think-100-of-global-warming-is-due-to-humans

... The land is expected to warm about 30% faster than the globe as a whole, as the rate of warming over the oceans is buffered by ocean heat uptake. This is seen in the model results, where land warms by around 4C by 2100 compared to 3C globally in the RCP6.0 scenario.

There is a wide range of future warming possible from different RCP scenarios and different values for the sensitivity of the climate system, but all show a similar pattern of declining future aerosol emissions and a larger role for greenhouse gas forcing in future temperatures.

The role of natural variability
While natural forcings from solar and volcanoes do not seem to play much of a role in long-term warming, there is also natural variability associated with ocean cycles and variations in ocean heat uptake.

As the vast majority of energy trapped by greenhouse gases is absorbed by the oceans rather than the atmosphere, changes in the rate of ocean heat uptake can potentially have large impacts on the surface temperature. Some researchers have argued that multidecadal cycles, such as the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), can play a role in warming at a decadal scale.

While human factors explain all the long-term warming, there are some specific periods that appear to have warmed or cooled faster than can be explained based on our best estimates of radiative forcing. For example, the modest mismatch between the radiative forcing-based estimate and observations during the mid-1900s might be evidence of a role for natural variability during that period.

A number of researchers have examined the potential for natural variability to impact long-term warming trends. They have found that it generally plays a limited role. For example, Dr Markus Huber and Dr Reto Knutti at the Institute for Atmospheric and Climate Science (IAC) in Zurich found a maximum possible contribution of natural variability of around 26% (+/- 12%) over the past 100 years and 18% (+/- 9%) over the past 50 years.

Knutti tells Carbon Brief:

“We can never completely rule out that natural variability is larger than we currently think. But that is a weak argument: you can, of course, never rule out the unknown unknown. The question is whether there is strong, or even any evidence for it. And the answer is no, in my view.

Models get the short-term temperature variability approximately right. In many cases, they even have too much. And for the long term, we can’t be sure because the observations are limited. But the forced response pretty much explains the observations, so there is no evidence from the 20th century that we are missing something…

Even if models were found to underestimate internal variability by a factor of three, it is extremely unlikely [less than 5% chance] that internal variability could produce a trend as large as observed.”

Similarly, Dr Martin Stolpe and colleagues, also at IAC, recently analysed the role of multidecadal natural variability in both the Atlantic and Pacific oceans. They found that “less than 10% of the observed global warming during the second half of the 20th century is caused by internal variability in these two ocean basins, reinforcing the attribution of most of the observed warming to anthropogenic forcings”.

Internal variability is likely to have a much larger role in regional temperatures. For example, in producing unusually warm periods in the Arctic and the US in the 1930s. However, its role in influencing long-term changes in global surface temperatures appears to be limited.

Conclusion
While there are natural factors that affect the Earth’s climate, the combined influence of volcanoes and changes in solar activity would have resulted in cooling rather than warming over the past 50 years.

The global warming witnessed over the past 150 years matches nearly perfectly what is expected from greenhouse gas emissions and other human activity, both in the simple model examined here and in more complex climate models. The best estimate of the human contribution to modern warming is around 100%.

Some uncertainty remains due to the role of natural variability, but researchers suggest that ocean fluctuations and similar factors are unlikely to be the cause of more than a small fraction of modern global warming. ...

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 14 Dec 2017, 12:23
by MilesAway
I hope this is incorrect because change like that is too fast for anything to adapt to!

If it is we should see massive technological change in the next ten years bracing for such a warning because it all leads to economics and that means hope for the future!

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 14 Dec 2017, 13:02
by HBS Guy
Solar radiation has been slightly low but this will change to slightly high before long, bumping up the temperatures.

As it is, major glaciers on Greenland (2 out of 3) and major glaciers on West Antarctica and glaciers and iceshelves on/around East Antarctica are retreating/destabilising. The sun starts pouring out a bit more radiation the melting of the ice kicks up into a higher gear.

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 14 Dec 2017, 14:57
by MilesAway
“Global sea ice levels” are the one to watch, imho!

That’s what the fake, read media, market is watching but all those legitimate markets are government intervened!

The tail wags the dog at the moment... simple as that! That doesnt mean Hollywood dictates : it’s only ever allowed to dictate!

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 17 Dec 2017, 16:26
by HBS Guy
American Meteorological Society joins others in determining that weather extremes could not have occurred without AGW:

Explaining Extreme Events from a Climate Perspective
This BAMS special report presents assessments of how human-caused climate change may have affected the strength and likelihood of individual extreme events.

This sixth edition of explaining extreme events of the previous year (2016) from a climate perspective is the first of these reports to find that some extreme events were not possible in a preindustrial climate[My emphasis. The events were the 2016 record global heat, the heat across Asia, as well as a marine heat wave off the coast of Alaska. While these results are novel, they were not unexpected. Climate attribution scientists have been predicting that eventually the influence of human-caused climate change would become sufficiently strong as to push events beyond the bounds of natural variability aloneMy emphasis.] It was also predicted that we would first observe this phenomenon for heat events where the climate change influence is most pronounced. Additional retrospective analysis will reveal if, in fact, these are the first events of their kind or were simply some of the first to be discovered


https://www.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/explaining-extreme-events-from-a-climate-perspective/

“climate change influence is most pronounced” is of course at the poles where albedo changes accelerate AGW.

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 17 Dec 2017, 16:29
by HBS Guy
For those without much intelligence or education—like Booby—the above link may be too hard. They can read:

https://insideclimatenews.org/news/13122017/extreme-weather-heat-harvey-climate-change-attribution-american-meteorological-society

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 17 Dec 2017, 17:47
by HBS Guy
From the Report cited above:

Global annual-mean surface temperature set a record
high in 2016
in at least three observational datasets—
GISTEMP (Hansen et al. 2010), HadCRUT4.5 (Morice
et al. 2012), and NOAA (Karl et al. 2015)—exceeding
the previous record set in 2015 (Fig. 3.1a). In contrast,
the last global mean annual cold record occurred
around 1910
. Record global warmth implies some
record warmth on regional scales as well (Kam et al.
2016), which can cause important impacts such as
thermal stress, coral bleaching, and melting of sea and
land ice (IPCC 2013). Decreased land ice, combined
with ocean heat uptake, contributes to sea level rise,
which can exacer


(Emphasis mine.)

So you can see that believing in an ice age now is ripest lunacy.

Booby thinks a storm dropping snow on the British Isles is a sign of an ice age. As the Barnacle told him but the idiot Booby ignored, precipitation does not imply cooling. Completely duped, brainwashed by an obvious liar.

Re: Scientists believe 100% of global warming is due to huma

PostPosted: 18 Dec 2017, 10:36
by HBS Guy
MilesAway wrote:I hope this is incorrect because change like that is too fast for anything to adapt to!

If it is we should see massive technological change in the next ten years bracing for such a warning because it all leads to economics and that means hope for the future!


Yes, DRAH, many species of plants and animals are going extinct or becoming in danger of extinction due to AGW. Animals can adapt better by moving to new, cooler pastures or up a mountain. Plants do the same but obviously slower.

Plants and animals can move higher up a mountain where it is cooler—but that has an obvious limit.

And there are other complications: caribou moving into the Antarctic at their usual time find spring is already there and midges are there in huge clouds, making life difficult for the caribou.

In England spring now comes 11 days earlier than it used to, making life hard for migratory birds who used to arrive at the start of spring.

As Squire pointed out, in the higher latitudes which normally have cold winters in summer the long hours of sunshine every day will put huge heat stress on people, plants and animals living there.