You would need to convert the projection to an equal area projection. Get rid of the dotted line and other stuff hiding the map first so you don't select them.I have absolutely no idea, I wouldn't even know how to find that out. here?
Using the magic wand, you compare the land pixels with the overall pixels on the map. That gives you a percentage.
Furthermore, if you want to know how big one continent is in sq km, you take the % and multiply it by the total area of the map.
If that sounds too complicated I could do it for you. I just need a clean copy just with land and water.
You have large landmasses close to the poles. These tend to be oversized when using a cylindrical projection compared to reality.Or do you think there is too much land
Overall, it's hard to tell. Just by looking at it. You might have more land than Earth but not that much.
On the world scale, I don't know. It could affect the planet's albedo since oceans retain more heat from the star than the forests, I think.What type of an impact could sea/land proportion have on a planet? Could it effect the climate?
But oceans can generate a lot of clouds from evaporation, which reduces the albedo.
The placement of the landmasses could play a larger role. Several millions of years ago, when the strait of Magellan was closed, the climate of Antarctica was much warmer. Warm waters from the Atlantic influenced the local climate.
Now the continent is completely cut off, surrounded by a could circumpolar current, a very strong one. It's a good thing since it prevent the ice from melting too fast.
Also, the climate in Antarctica was warmer because the atmospheric composition of the planet was different. The greenhouse effect was much stronger then leading to more uniform climates planet-wide.
Back to your map, the impact globally is hard to estimate, or probably small. On the local level, large landmasses produce monsoons.