[bobdihi (OP)]

    Would increase in Sun's temperature effect Earth's temperature? We talking about 1.5 degree celsius  temperature  increase on Earth would be catastrophic. So what increase in suns temperature would cause such a increase on Earth?
 
 

[evan_au]

Would increase in Sun's temperature effect Earth's temperature?

The "black body" temperature of the surface of the Sun is around 5770K (around 5500C), although some areas like sunspots are slightly cooler (around 4000K).
The "black body" temperature at Earth's orbit is around 258K (-15C) - although I'm not sure how to calculate that....
Earth's atmosphere retains enough heat that Earth is not a snowball (although that has apparently happened in the past).

To increase Earth's temperature by 1.5C, you would need to increase the Sun's surface temperature by about 35C. In the century or so since the discovery of spectroscopy, I am sure that astronomers would have been able to detect a change like this.
As Halc says, an increase in the diameter of the Sun would also heat the Earth. However, astronomers have been reporting eclipses for millenia, and the known size and orbit of the Moon provides a very precise gauge to measure the size of the Sun.
- There are stars that change size on a regular basis, but the Sun is not a Cepheid variable.
- Astronomers using helioseismology measure changes in the size of the Sun very precisely

Astronomers understand a lot about stellar evolution (and a moderate amount about the Sunspot cycle).
- Changes in the Sun cannot account for the rapid warming over the past century
- Scientists and economists have searched for the impacts of the 11/22 year Sunspot cycle, and not found any
- We are not emerging from a pause in the Sunspot cycle
- Earth's orbit has not changed dramatically in the last few hundred years
- So recent increases in Earth's average temperature must be occurring in the last 100km = Earth's atmosphere
- And the most visible change has been the increase in manmade CO₂ and other greenhouse gases in the past century

See: https://en.wikipedia.org/wiki/Sun#Photosphere

[Rodin1880]

Decreasing Reflectivity Increases Temperature... The square footage of ice that has been removed from the earth's surface in the last 700 million years is well beyond half the square footage of the earth, as a result the speed at which our planet will warm will, naturally become faster, naturally increasing the melting of the remaining ice, which naturally decreases the reflectivity faster, warming our planet faster... Realize it took 40,000 years to melt the ice from halfway up the US to halfway up Canada... I don't believe we have another 40,000 years left, and there is nothing we can do about it short of increasing our reflectivity by turning everything we can white, which I also don't believe would work because we aren't that significant on the planet...
As far as the heat of the sun having an affect, how hot was it 700 million years ago? 40,000 years ago? 1,000 years ago? how about 200 years ago?... As far as we know the sun temperature changes 10 times your 1.5C every 500 years without affect, making your question impossible to answer...
What we do know is how much ice covered our planet and when, making the ice cover the best gauge for temperature of the earth, and allowing us to understand that if we intend on surviving the next 40,000 years we better learn how to swim...

[Petrochemicals]

Given that the glaciation cycles and the far far increaced reflection of sunlight during thoes times is overcome by simply altering the angle of the earth and  altering the eccentricity of the orbit, the increace in solal output and decreace in solar output over a long term period ie 100s of years would have a huge effect. It takes more time than the solar spot cycle to have an inpact.

 Altering the permanent long term temperature  of the sun would no doubt lead to a smaller sun also as the sun expands to an equilibrium of its temperature mass and volume,

[Bored chemist]

there is nothing we can do about it short of increasing our reflectivity by turning everything we can white, which I also don't believe would work because we aren't that significant on the planet...

Why not?
We made the entire atmosphere  slightly darker.

[jeffreyH]

We need to stop thinking strictly in terms of CO2. The water cycle is equally important.
https://www.scidev.net/global/climate-change/news/human-activity-changes-global-water-vapour-pattern.html

[Bored chemist]

We need to stop thinking strictly in terms of CO2. The water cycle is equally important.
https://www.scidev.net/global/climate-change/news/human-activity-changes-global-water-vapour-pattern.html

It's probably more important; but it's not the one we are changing.

[Petrochemicals]

We need to stop thinking strictly in terms of CO2. The water cycle is equally important.
https://www.scidev.net/global/climate-change/news/human-activity-changes-global-water-vapour-pattern.html

It's probably more important; but it's not the one we are changing.

You cannot watch the news much BC

https://www.independent.co.uk/environment/hothouse-earth-climate-change-global-warming-greenhouse-gas-sea-level-arctic-ice-a8481086.html

Once a critical vapor content is reached its self sustaining apparently.

[Bored chemist]

We are adding CO2 to the air, but we are not adding so much water, because the water content of the air is more or less defined by temperature.

[yor_on]

This one doesn't belong here, especially not as it is so f*ng American politically infected. If they would decide the whole question would be one of informing Earth that the Republicans had won, and now Earth just have to adapt. It's not even funny reading some of the reply's. Move it to " The Environment " where I hope it fits a little better.

[Petrochemicals]

This one doesn't belong here, especially not as it is so f*ng American politically infected. If they would decide the whole question would be one of informing Earth that the Republicans had won, and now Earth just have to adapt. It's not even funny reading some of the reply's. Move it to " The Environment " where I hope it fits a little better.

Lol

The correct answer is therefore,

"The same as burning fossil fuels for 75 years"

[yor_on]

Trolling?

Move the thread.

[andrew7278]

Yes, it can be occur.

[andrew7278]

Thanks for the suggestions.