I don't have a problem with planting trees, but I am not convinced that planting trees will address global warming because trees are seen as a commodity instead of infrastructure.  Once the trees are well established there will be pressure to cut them for timber. 

Also, there is the land use issue - as fast as we may be able to plant trees, other human beings may be cutting them down on other parts of the planet.  

Do you have any links to information/plans/proposals for tree planting as a solution? 

Billions of Trees Must Be Planted to Restore Lost Forests
To make up for the loss of trees over the past decade, 130 million hectares (or 1.3 million square kilometers), an area as large as Peru, would have to be reforested. Accomplishing that would mean planting about 14 billion trees every year for 10 years in a row, the equivalent of every person on Earth planting and caring for at least two seedlings annually.

This 14 billion trees for ten years would make up for tree loss over the past decade. That sounds like a holding action to me, I did not find projections as to how many trees we might need to plant to create a carbon sequestration plan that would address global warming. Plus, this approach, admirable as it is, does nothing to reduce accumulation of greenhouse gases that are largely related to tailpipes and smokestacks.

I still think we have to start with tailpipes and smokestacks to address the warming and I think it can be an economic renaissance for the US.

Plant trees? Yes, certainly.

"A society grows great when old men plant trees whose shade they know they shall never sit in." -- Greek proverb

But I believe if we want to reduce global warming, which is happening and is bad from an anthropocentric pov, then we have to look at the source of the problem - tailpipes and smokestacks - the burning of fossil fuels. Time to evolve.

http://www.cem.msu.edu/~cem181h/projects/96/iron/cem.html

  Iron is a limiting nutrient for the plankton, the growth of plankton cannot increase unless the amount of iron in the water increases. By introducing extra iron into the environment, plankton growth is accelerated. The increase in plankton alows for more carbon dioxide to be removed from the atmosphere.

Probably won't cost 5 Trillion dollars 

as the carbon dioxide in the atmosphere rises, the carbon sequestration in the sea is increasing and that is changing the ph of the ocean.  With slightly more acidic oceans, we begin to get a problem where the shells of ocean life are endangered.  Here is a story from July 2006 about that courtesy Mongabay.

Increasingly acidic oceans harm marine life mongabay.com
July 5, 2006

I think the long and short regarding the health of the oceans is the same story as regards the health of the continents as greenhouse gases continue to rise, the world becomes a little more precarious environment for many existing species.  I think that includes human beings.  

That does not have to be seen as gloom and doom story, the real story is that we can choose to address the accumulation of greenhouse gases through a comprehensive sustainable energy policy that creates jobs, reduces our dependence on oil from Saudi Arabia, and is good for the living things on the planet.

I have a dream about clean, sustainable energy infrastructure.  

done voluntary, no forced "huge" changes!

“America passes the critical gate test. Open the gate and see where people go – in or out. This is still the country people flock to.” George Will

has come to that same conclusion.  The folks who developed the design are also saying it is a crazy idea, and should only be a last resort. 

I don't think much of it because it serves only purpose - reducing sunlight, it doesn't create energy or reduce accumulation of greenhouse gases that are going to be a problem for ocean life.

I think it is interesting technological solution, but misses the mark because the root problem, imho, is the burning of fuels that create greenhouse gases and I think the root solution is to work on clean, sustainable energy infrastructure instead of parasols in space.  

But, for any of you who think that the solar irradiance is the primary cause of global warming, the parasols in space should have appeal that will not accrue to a clean energy infrastructure.  

"If given the education and the opportunity, people will make the right decisions." I don't think so. When even the best educated people enter a freeway, they do so with nearly total disregard for the impact they have on everyone else on the road. When I merge onto I-5 it is far from clear to me how much I am contributing to congestion that affects thousands of other people on the road. My personal decision does not include an estimate of the social costs of my actions. That is why we enforce things like carpool lanes, metered on-ramps, and tolls. That is far from nanny-statism. It is simply confronting issues of scarcity and congestion.

To a great degree this is a non-issue but a useful straw man. I don't think that banning plastic grocery bags or requiring deposits on plastic water bottles represent huge changes in lifestyle. So let's stop talking about these vague changes that no wants to adapt to and speak to the specifics. And let's drop the nanny trope while we're at it.  

and essentially it's another parasol in the sky, but using dust clouds instead of high tech umbrella thingies.  Same problem as the umbrellas for me, might have unintended consequences.

I am inclined to think that the natural environment is kind of a good thing, so instead of pumping more stuff into the sky to counteract other stuff we are pumping into the sky, I think we ought to focus energy on reducing the first stuff we are pumping into the sky.  

Here's something from August 2007, National Geographic:

A controversial theory proposes mimicking volcanoes to fight global warming. But throwing sulfur particles into the sky may do more harm than good, a new study says.

The temporary solution would pump particles of sulfur high into the atmosphere—simulating the effect of a massive volcano by blocking out some of the sun's rays. This intervention, advocates argue, would buy a little time to reduce greenhouse gas emissions.

But as well as cooling the planet, the sulfur particles would reduce rainfall and cause serious global drought, a new study says.

"It is a Band-Aid fix that does not work," said study co-author Kevin Trenberth of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado.

It's just one of several drastic measures proposed to combat global warming, now that most scientists are in agreement that carbon dioxide, primarily from burning fossil fuels, is changing Earth's climate.

liberal fascist nannies?  I don't know about that one.  New collectivist union or something?  I thought Rob's naming Gug and Mike as liberal fascist nannies or whatever seemed unresponsive to the thread which is about solutions to global warming.  But I am generally ok with getting lumped with Gug, so I guess the question becomes when is payday and do I get dental as a liberal fascist nanny?