How much warming do we cause?

Question

How much of the warming since 1850 do you think has been caused by

A Human GHG emissions

B Solar Output increases

C Urbanization and poort station situation

D Other (like ENSO, ocean currents etc.)

I'm going to say

A 45%

B 35%

C 10%

D 10%

What do you think?

Answer 1

E 0%

Answer 2

Human emissions are almost negligible (0.28%) compared to all other emissions, and solar activity is the driving force. Also there have been lots of reports of bad placements of measurement stations and most of the ones in the colder parts of the world no longer exist.  With that info, I'd say:

A 1%

B 75%

C 9%

D 15%

Answer 3

We have a problem that you have left out secondary effect, which is more important by far than C and D combined.

I place a value of 0% on D, even though it contributes to reduction in northern reflectivity.

Secondary effects are the effect of warming on warming. When we have warming we get reduced reflectivity from snow and glaciers, which are significant  but much more significant is a reduction in global dimming. Warming means that we have less cloud cover, and thus major increases in the energy reaching earth.

warming means we have higher water vapor content in our air with lower humidity.

(Yes, this is not a mistake.) Because water vapor is earth's most significant greenhouse gas, not only do we receive more light from reduced dimming, we also retain more heat.

Reduced cloud cover also means we get more drought. But drought means we get less CO2 uptake by plants on land. ( By contrast, ocean plants capture so much CO2 that they create great dead zones when ocean vegetation piles up and dies, forced deep into the water, and decomposes in the water releasing the CO2 and depriving animal life of oxygen.)

I place a percentage of about 60% on secondary causes. That percentage is rising.

Solar variation may account for 10% at most. this is declining.

Human GHG emissions may then be responsible for from 90 to 30 %... The reason for the high upper and lower variation is that secondary effects  are dependent on primary, initially.

Human actions may have set the ball in motion 90%, but by now secondary effects have taken over so that even by removing the primary human effect, our secondary effects may keep warming going... Current year emissions are not as significant as a contributor as is our loss of CO2 absorption from drought and deforestation.

If we stopped all fossil fuel emissions today, we would continue to see our temperatures rise, and not just because of elevated levels of our emissions. We now have less CO2 being removed from the atmosphere, more water vapor in the atmosphere, and arctic methane beginning to escape.

Answer 4

it dsnt matter what the percentages are buh hw we can help save our planet and our lives. poeple take this as a joke buh if theres no planet people theres no us and technically we are to blame for global warming so reduce ur carbon foot print or recycle at least

x x x

Answer 5

Hmm since 1850 is tough because that's a long time.  Increased solar output was responsible for a significant fraction of the earth 20th century warming.  Overall I'd say about

A - 55%

B - 40%

C - 0%

D - 5% (but 0% for ENSO)

Over the past 30 years it's more like:

A - 90%

B - 5%

C - 0%

D - 5%

Answer 6

There is no way to know.  You picked 1850 which is a particularly cold time.  I would only say that "D other" is most likely underestimated by you and Dana.  Dana is an alarmists and alarmism depends on the supposition that you have a high understanding of natural systems.  I don't think we do.

Note, Just to be clear: Other doesn't necessarily include your examples.  There are many things we don't understand about climate and how they affect each other.  Answering the question with actual percentage would indicate knowledge that doesn't exist.  Dana can grab a number out a hat or wherever but it is meaningless.

Answer 7

Human - None, as man cannot affect the climate.  Over the last 100 years, it is claimed man has added 100 ppm of co2 to the atmosphere.  This is just one molecule of co2 per 999,000 other molecules per year.

How much warming can one molecule per million do?

Man made global warming is far over blown.

Answer 8

I am a "Green" person completely for the environment, i've tried seeing it through the peoples eyes who say that Global Warming isn't Happening... Well i believe it is but not completely because of humans in Earths history the Earth has Heated and Cooled many times, Humans may not be the only reason for Global warming but we are contributing, We did not Cause Global Warming because it's happened many times even before their were humans were just speeding up the process by ALOT. So i'd say A.

Answer 9

Greenhouse gas change 1850-2007:

+0.847 C (includes forcing from CO2, N2O and CH4, halocarbons excluded. Uses climate sensitivity of .51 K W^-1m^-2)

Sulfate cooling change 1850-2007:

-0.034 C (Uses sulfate forcing coefficient of -.00055 K TgS^-1)

Net anthropogenic temperature change since 1850:

.847 - .034 = +0.813 C

Total global temperature change 1850-2007:

.850 C

(According to UK's Hadley Centre HADCRUT3 dataset:

http://hadobs.metoffice.com/hadcrut3/dat... )

Human-caused percentage of global warming, 1850-2007:

.813 / .850 = 96%

Solar irradiance 1850-2007 increased by 0.08 W m^-2 (which actually masks a larger mean increase because 1850 was near solar maximum and 2007 was at solar minimum). That would account for a warming of .04 C using the same climate sensitivity, which is essentially all of the remaining change. (See Lean's reconstruction of solar irradiance at:

http://data.giss.nasa.gov/modelforce/sol... , although I adjusted Lean's numbers downward by 1.54 W m^-2 to closely fit the satellite data in the period after 1979.)

El Niño / Southern Oscillation records only go back as far as 1866, so it's impossible to say for sure. But the long-term effect of El Niño is near zero (even though short-term effects can be quite significant) and given that everything else balances, I'd guess that there isn't much there.

Answer 10

Even the proponents of GW say that we may contribute 33% to the "observed".5 degree temperature increase------

So if I were to agree with them then humans caused about

.17 tenth of a degree of the warming-- folks that is a very small number ! However I do not agree with them.

http://science-sepp.blogspot.com/

Answer 11

Good question, though 1850 will be a little rough because that was long before I was born, since im 14 in all but....

Id say"

A-50%

B-35%

C-5%

D-10%

I think that because Green house gas emissions can add to the fact that the sun will go out eventually, that's why its been having all of these problems with sun spots in the past. C- I dont really think has much of an influence....

Over the past 30 years would be more like:

75%

15%

0%

10%

Thanks,

Courtney D.

Answer 12

It doesn't matter what the percentages are. The fact is that the earth is into a warming phase whether we caused it or something else. Now what do we do about our little portion of earth? As for me, the weather is actually cooler than before and that is a blessing for my area. So how can I increase global warming more than I already have?

Answer 13

I will say this.

Temperature change =.7 degree C.  (ignoring some dips)

.3 pre 1940, .4 post 1940

A: 45%

B: 45%

C: Technically 0%  However the Urban heat island and the location of temperature may have an effect of +/- 10% on the temperature record.  

D:10%

It would be easier to say D+A~55%