Decline in solar output unlikely to offset global warming

[Ziggy Stardust]

Decline in solar output unlikely to offset global warming

23 January 2012 - New research has found that solar output is likely to reduce over the next 90 years but that will not substantially delay expected increases in global temperatures caused by greenhouse gases.

Carried out by the Met Office and the University of Reading, the study establishes the most likely changes in the Sun's activity and looks at how this could affect near-surface temperatures on Earth.

It found that the most likely outcome was that the Sun's output would decrease up to 2100, but this would only cause a reduction in global temperatures of 0.08 °C. This compares to an expected warming of about 2.5 °C over the same period due to greenhouse gases (according to the IPCC's B2 scenario for greenhouse gas emissions that does not involve efforts to mitigate emissions).

Gareth Jones, a climate change detection scientist with the Met Office, said: "This research shows that the most likely change in the Sun's output will not have a big impact on global temperatures or do much to slow the warming we expect from greenhouse gases.

More here:
http://www.metoffice.gov.uk/news/releases/archive/2012/solar-output-research

No link to study ... googling.

Found it, but you need membership

http://www.agu.org/pubs/crossref/pip/2011JD017013.shtml

 

[G-Max]

We already have a global warming thread.

 

[El_Machinae]

Here's the abstract, though.

During the 20th century solar activity increased in magnitude to a so called `grand maximum'. It is probable that this high level of solar activity is at or near its end. It is of great interest whether any future reduction in solar activity could have a significant impact on climate that could partially offset the projected anthropogenic warming. Observations and reconstructions of solar activity over the last 9000 years are used as a constraint on possible future variations to produce probability distributions of total solar irradiance over the next 100 years. Using this information, with a simple climate model, we present results of the potential implications for future projections of climate on decadal to multi-decadal timescales. Using one of the most recent reconstructions of historic total solar irradiance, the likely reduction in the warming by 2100 is found to be between 0.06 and 0.1K, a very small fraction of the projected anthropogenic warming. However if past total solar irradiance variations are larger and climate models substantially underestimate the response to solar variations then there is a potential for a reduction in solar activity to mitigate a small proportion of the future warming, a scenario we cannot totally rule out. While the Sun is not expected to provide substantial delays in the time to reach critical temperature thresholds, any small delays it might provide are likely to be greater for lower anthropogenic emissions scenarios than for higher emissions scenarios.

 

[Ziggy Stardust]

We already have a global warming thread.

It got closed for being over 1000 posts. I wanted to post it there but couldn't

edit: Thanks El_Mac, I should have included that.

 

[Winner]

Any news on the "global dimming" phenomenon and how it might influence global warming?

 

[Cutlass]

Any news on the "global dimming" phenomenon and how it might influence global warming?

Recent trends seem to indicate the possibility that global dimming is peaked or may be reduced. Too early to tell. However recent regulations to have ships at sea burn cleaner fuel is expected to reduce dimming, because ship exhaust is a major cause of dimming over the oceans. So the oceans should see cleaner sunlight in coming decades.

 

[Winner]

Recent trends seem to indicate the possibility that global dimming is peaked or may be reduced. Too early to tell. However recent regulations to have ships at sea burn cleaner fuel is expected to reduce dimming, because ship exhaust is a major cause of dimming over the oceans. So the oceans should see cleaner sunlight in coming decades.

It's a bit ironic that better environmental standards will probably reduce the dimming effect which has so far been helping to offset the worst of global warming.

 

[Cutlass]

It's a bit ironic that better environmental standards will probably reduce the dimming effect which has so far been helping to offset the worst of global warming.

That happens from time to time. There are a lot of issues that need to be addressed for one reason or another. And sometimes they are in conflict. It happens in a lot of issues.

 

[El_Machinae]

It's a bit ironic that better environmental standards will probably reduce the dimming effect which has so far been helping to offset the worst of global warming.

It's amusingly ironic, honestly. It's somewhat of a problem of impact and effect. 'Better environmental standards' pay off today, in the form of direct health & ecosystem benefits. There was a recent paper that pointed out that impacting methane and 'carbon soot' pollution would be a double-whammy of benefit. Reducing these two pollutants would improve human health (and crop health) more than the cost of implementation and would also help delay AGW concerns.

So, we're motivated to get cleaner air if we're going to breathe it. That some of those pollutions type are causing dimming is of some concern, because we know that we're going to reduce that pollution if we can afford to.

On the other hand, while the dimming can mask AGW, it can't mask oceanic pH changes.

 

[BasketCase]

It's a bit ironic that better environmental standards will probably reduce the dimming effect which has so far been helping to offset the worst of global warming.

More than a bit ironic. And also, the above has already happened. Back in the 70's, pollution was a big deal but global warming was pretty much unheard of. Science knew of global warming, but nobody in science or out really cared about it. "Cleaning up the planet" meant getting rid of all the black particulate crap coming out of smokestacks and car exhausts. We Americans were reducing particulate soot without reducing CO2 production. For all we know, this one factor could be the entire cause of the current (alleged) warming trend.


So here's the Sixty-Four-Dollar question: how much CO2 do we need to eliminate from the atmosphere in order to offset global warming--without making the same mistake all over again?

That's the problem with trying to keep nature in balance. Reduce AGW too far and we'll merely knock the planet out of balance in the other direction. And that would be a lot worse, because an ICE AGE happens to be lurking in that other direction.

 

[warpus]

It's not a problem.

The more we clean up our act, the healthier the planet will be. There's nothing to balance.. The onus is on us, as a species, to not pollute as much as we do.

 

[BasketCase]

If the next Ice Age goes off, the planet will be a near-dead ice cube, and most of the species currently on it will go extinct. There's no possible way that could be called "healthy".

So forget it.

 

[History_Buff]

That's the problem with trying to keep nature in balance. Reduce AGW too far and we'll merely knock the planet out of balance in the other direction. And that would be a lot worse, because an ICE AGE happens to be lurking in that other direction.

But adding CO2 to the atmosphere would be easy. If there's any universal truth to humanity as a whole, it's probably that we really like to set stuff on fire

 

[BasketCase]

No thanks. Global warming is a random hodgepodge of good and bad things. Much safer than allowing a much worse crisis (an Ice Age, which has very little in the way of good outcomes about it) and then trying to fix it. I'm staying on the warming side of the fence until more science is done.

 

[Crezth]

No thanks. Global warming is a random hodgepodge of good and bad things. Much safer than allowing a much worse crisis (an Ice Age, which has very little in the way of good outcomes about it) and then trying to fix it. I'm staying on the warming side of the fence until more science is done.

Who says averting global warming would cause an ice age?

 

[peter grimes]

...most of the species currently on it will go extinct.

I think you're wrong here. At least, that hasn't been the case during the previous recent glaciations. For most of the species currently around to go extinct would imply a mass extinction event. Ice Ages aren't mass extinctions, at least the recent ones.

 

[BasketCase]

Ohhhh, my Gooood!! Dude, every Ice Age has been a mass extinction event. (one exception being the "Little Ice Age" which wasn't really an Ice Age but which did cause a whole lot of grief)

Who says averting global warming would cause an ice age?

This guy.

In his overdue-glaciation hypothesis, this guy claims that an incipient ice age would probably have begun several thousand years ago, but the arrival of that scheduled ice age was forestalled by the activities of early farmers.

Also many other climatologists, based on the fact that the current interglacial is running longer than past ones. The Earth is overdue for an Ice Age.

 

[Crezth]

This guy.

Also many other climatologists, based on the fact that the current interglacial is running longer than past ones. The Earth is overdue for an Ice Age.

Isn't he effectively arguing for AGW, however?

I'm not sure how stopping the rise of temperatures now would actually cause them to backslide, though, and I don't see much on that page that claim that, either.

 

[Dida]

I thought the sun's output is supposed to increase as it ages?

 

[BasketCase]

Isn't he effectively arguing for AGW, however?

Not specifically, no. He says human activity prevented an Ice Age from happening. Which is probably the only reason the human race exists at all. That's a good thing. The only downside being that you and me are arguing with each other again.

I'm not sure how stopping the rise of temperatures now would actually cause them to backslide, though, and I don't see much on that page that claim that, either.

This is one of those cases where "A therefore B" does correctly imply that a lack of B results in a lack of A. If a particular human activity prevented an Ice Age, then a lack of said human activity will allow an already-overdue Ice Age to occur.