How much of our energy comes from the sun?

[wobs]

I would tend to agree with you, either directly of indirectly I would hazard a guess that the vast majority of the planets energy comes from the sun. (I stress that is a guess though!)

As I said, we get about 173PW from the sun,

About 30% of the incoming solar radiation is reflected back into the terrestrial atmosphere by the earth; this is called the “albedo” of the earth, which is defined as the ratio between the reflected and incident radiation and denoted by a. The reflection is caused by various phenomena, such as backscattering (7%), reflection by clouds (17%), and reflection by the earth’s surface (6%). Then, about 19% of the incoming solar radiation is absorbed by the water vapor, dust, and ozone molecules present in the atmosphere, while about 4% is absorbed by clouds. The remaining 47% is absorbed by the earth.

About 76PW actually heats the Earths surface, and 22% of the incident extraterrestrial solar radiation, amounting to 40 PW, is consumed by the hydrological cycle (rain, evaporation etc), so all the lakes, and rivers etc. got there by this process.

If we used all the 76PW in solar panels at 20% efficiency, we would get 15PW, which would equate to about 1000 times what we consume now. At 3% growth, thats about the year 2240.

The intensity of geothermal heat is comparatively low with respect to solar energy intensity, namely ~0.1 W/m2 versus ~240 W/m2 for geothermal solar, respectively.

Put another way, the total solar energy available could be considered as 117PW
Geothermal - 0.044PW
Tidal - 0.003PW
But current consumption is about 0.015PW.
Of that 0.015PW, only a tiny fraction will be from solar energy directly (either PV or thermal)
Lots more info here:
http://www.google.co.uk/url?sa=t&rc...LMuqmm5xWqEvQmPKMs0dHkA&bvm=bv.56146854,d.d2k

 

[ericmark]

All the figures released seem to change according to who they come from hence I would not call them facts.

One of the questions in the BBC survey to see what we know about our world was:- Question: In the year 2000 the total number of children (age 0-14) in the world reached two billion. How many do UN experts estimate there will be by the year 2100?

The answer was 2 billion population is no longer increasing it would seem.

My concern is by exaggerating claims and publishing half truths the missing out of the word directly is a good example we start to question what we are told and disbelieve the main bulk.

We are told we have global warming and if we look at history we see the dress worn by Romans in Britain would be inappropriate in today's climate so clearly it is colder now. Yet also we see how fairs were held on the frozen Thames so from Roman to today the temperature has changed and we can't just look at single events. Looking at early this year we had more snow at home than I can remember over last 55 years.

With so many conflicting stories about global warming I now don't trust any of the figures released. I will save energy to save money but not for sake of the planet. I have come to the conclusion most of it is just a way to generate money.

Unfortunately there is a lot of damage being done as a result. I see people stealing wood from woodlands left to decay to help the woodland regenerate and then being burnt in grossly inefficient wood burners with particular emissions which years ago produced the smog which the clean air acts tried to get rid of. This is all because of the misguided drive to try to get us to save energy.

The catalytic exhaust cleaner must be one of the worst things we ever adopted meaning lean burn engines have not been developed causing far more fuel to be used in our cars. This points to the idea that all to do with making money and little to do with saving the planet.

 

[JBR]

I completely agree.

Such 'statistics' are reflected in the terminology used by the prophets of doom: it started as 'global warming' and was then quickly renamed 'climate change' to cover their backs!

Personally, I don't believe a word of it and I think it's a shame that so many people are being taken in by this farce.