Bullshit. You should always look at a period long enough to get rid of the noise. If you do that with ocean levels, you'll see that the long term trend is undeniably up.

https://upload.wikimedia.org/wikipedia/commons/0/0f/Recent_Sea_Level_Rise.png

You can also see that the short time data is very noisy.

The question was who we should trust climate scientists or historians. Between the two, I'd put my money on the climate scientists, given any reasonable definition of the term.

But of course, if you can find some good research done by a historian about the global temperature record, I'm sure people would be interested.

Modern farmers aren't just planting potatoes. Besides, if you want to make a point that the MWP was warmer than today, the data needs to be calibrated to an actual temperature, and the data needs to be global.

Anecdotes about Viking farming in Greenland provides neither.

Historians better get busy and get their asses back to Greenland, to document modern farming:

"Trees are growing and the fields are full of potatoes, lettuce, carrots and cabbage" to be sold at the local market, explains Anders Iversen, who heads a plant nursery near Qaqotorq in the south.

Temperatures are warmer now, with the mercury sometimes rising above 20 degrees Celsius (68 Fahrenheit) in summer, he says.

"If global warming continues, we will be able to grow even more kinds of vegetables during a longer season," he adds.

http://www.terradaily.com/reports/Global_warming_impacting_Greenlanders_daily_lives_999.html

Climate scientists, of course.

What historians are you talking about, and did they collect temperature data from all over the globe ?

How can a single rocket, a tube filled with pork, cost $10 billion? Please explain.

FTFY. Now the answer is obvious.

Back to the beginning: if a majority of scientists agree that the MWP was cooler than today, what would be a valid reason, for non-scientists, to assume the MWP was actually warmer ?

Yet, everybody agrees that earth has been cooling down since around 2000.

No, only a couple of crackpots agree on that. Here's a link of global temperature anomalies in tabular format:

http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.txt

Average for 2000-2009 was +0.52
Average for 1990-1999 was +0.31
Average for 1980-1989 was +0.18

Doesn't look like it's getting colder, especially if you consider that every single year since 2000 has been warmer than the 1990-1999 average.

"majority" arguments don't work with science.

It doesn't work within science. It works fine when trying to determine policy based on science. Everything we teach the kids at school is based on scientific consensus. That's why we teach the theory of evolution, even though there are some people that disagree. Even if there's no guarantee that scientific consensus is correct, it's still the best thing we have.

Nobody's trying to outlaw CO2. People just want to prevent it from rising too far.

Keeping CO2 below 450 ppm isn't going to harm any plants, when it has been below 350 ppm for hundreds of thousands of years.