Climate change "facts"?

Bob Carter is a geologist and a global warming denier. His recent opinion piece in The Age titled "An inconvenient fallacy" shows him using his own facts. Not being an expert on most of the issues, the Phactor will confine his criticism to just one fact. "Fact 3. Atmospheric carbon dioxide is beneficial. In increasing quantity it causes mild though diminishing warming (useful at a time of a quiet sun and likely near-future planetary cooling) and acts as a valuable plant fertiliser. Extra carbon dioxide helps to shrink the Sahara Desert, green the planet and feed the world. Ergo, carbon dioxide is neither a pollutant nor dangerous, but an environmental benefit."
First of all, does this guy think the Sahara is a desert because of the lack of CO2? OK, well, guess he doesn't garden or have house plants. Probably just a pet rock, and it seldom needs watering.
Next, the stuff about CO2 and plants is sort of OK, but when temperature gets added to the equation things change, and not only won't the Sahara get greener, the Amazonian rainforest might get a lot grassier, i.e., tree death may lead to a grassland savana replacing tropical rain forest. This change-over releases more CO2 because all those woody stems are store houses of CO2 that begin decomposing after the tree dies. This happens all the time, but if there are fewer trees to make wood, more CO2 will be released than taken up. Trees die because the rate of plant respiration continues to go up as temperature goes up, but photosynthetic rate tops out and then begins to decline. This means at higher temps more respiration, less photosynthesis. In one of the few long term studies, tropical tree mortality and average temperatures are negatively correlated; trees just respire themselves to death at higher temperatures. So our geologist is only correct if temperatures remain steady, but average temperatures are positively correlated to atmospheric CO2. Now of course the biologists who have been doing the study, my friends the Clarks, get their salaries and research money from grants, and their data and analyses that get published all have to get by lots of reviewers taking critical looks at their data, ideas, methodology, analyses, knowledge of science, etc., and they've been very successful for nearly 3 decades now. And in just 10 mins the Phactor let the air our of one of Prof. Carter's "facts". So who you gonna go with?

Plant Respiration Question

Dear Phytophactor,
My fiance and i have recently gotten into a debate about plant respiration.
She is worried about the amount of CO2 that plants may be giving off at night and prefers that we do not have them in the bedroom where we sleep.
I love plants....but i love her more.
So, the question is, what is the ratio of O2 to CO2 that plants give off? How much CO2 can a single medium size house plant give off in one night? How much CO2 is being produced if I have a bedroom full of plants? (five or six)?
I have searched the internet, and many sites agree that plants give off CO2 at night when they are in the process of respiration, but no one seems to provide any information about the exact amount of CO2 that plants actually produce.
Thank you!
Matthew

The Phytophactor responds:
Dear Matthew,
You make the Phactor feel like the Car Talk guys when you send me a question like this. The basic idea is correct; plants respire and give off CO2, all the time, and at night the respiration is not off set by photosynthesis, but here's the critical thing to understand. Plants respire at a much, much lower rate than a nice warm-blooded mammal. So if your fiance is worried about oxygen depletion and CO2 buildup at night, guess who ends up in another bedroom? Alternatively you could keep your bedroom really cool at night which will slow down plant respiration even more, while at the same time providing a good reason for keeping your warm carbon dioxide producing body around. Since your plants do grow, your plants are capturing more CO2 during the day than they release via respiration all day. The two cats sleeping on my bed respire a lot more than a whole roomful of plants. So plant respiration just isn't a problem, and here the Phactor stops short of saying a silly concern although it is, but I did hear this concern once with respect to giving plants to hospital patients. Even if plants gushed carbon dioxide at night hospital rooms and your bedroom are not sealed boxes, so gases can easily diffuse to equilibrate any tiny differences that might occur. So sleep well, the plants and their respiration aren't a problem; if they were we'd have be careful about entering my greenhouse or the rainforest at night, and both of them have far greater mass of plants respiring than your bedroom. Hope this helps you sleep in restful assurance, providing you do not handle being on the winning side of this debate with a certain air of superiority and condescension (And depending upon the particular nature of your fiance, please recall the scene in the 1st Star Wars movie where the R2D2 is beating Chewbacca at a chess-like game. Let the Wookie win may be very good pre-maritaladvice.).