Is it true ''Nature can not be manipulated by human hands'' someone said that! What is farming then?

Never heard it phrased exactly that way but you do see people trying to question humanity's ability to change the composition of the atmosphere. The actual scientific reasons why we know this is happening usually don't work for most people making that argument, so I like to show this picture of the Earth at night. And remind them of a few facts to go along with it: 

1. >80% of those lights are powered by fossil fuels. 

2. Those are just lights that you can see. It doesn't include other forms of energy, like driving cars, powering machinery, HVAC, chemical processes, and many many others -- all of which are also using fossil fuels. 

3. You are only looking at this image for a few seconds. But the reality of this image continues after you look away -- this energy is being used every second, and has been every day, every month, every year for decades and decades. 

4. Depending on what kind of device you look at it, that image might appear to you anywhere from 2 to 6 inches across. At that scale, the troposphere -- where all of the CO2 is being pumped in to and all weather occurs -- would be as thin as the thinnest hair on your arm. 

Farming is the redirecting of Mother Nature; they do not change it, instead they use it in a positive floormate to grow FOOD>

Due to the stupidity of your question, I wonder if your ancestors walked upright.

From Wikipedia:

Instinct or innate behavior is the inherent inclination of a living organism towards a particular complex behavior. The simplest example of an instinctive behavior is a fixed action pattern (FAP), in which a very short to medium length sequence of actions, without variation, are carried out in response to a corresponding clearly defined stimulus.

Any behavior is instinctive if it is performed without being based upon prior experience (that is, in the absence of learning), and is therefore an expression of innate biological factors. Canada geese fly south due to their innate ability to detect the onset of winter.  Sea turtles, newly hatched on a beach, will instinctively move toward the ocean. A marsupial climbs into its mother's pouch upon being born. Honeybees communicate by dancing in the direction of a food source without formal instruction. Other examples include animal fighting, animal courtship behavior, internal escape functions, and the building of nests. Though an instinct is defined by its invariant innate characteristics, details of its performance can be changed by experience; for example, a dog can improve its fighting skills by practice.

The idea that humans are so insignificant that they have no effect on nature is a purely religious belief, and as your example shows it is a belief that’s easily falsified.

Well I've just tested it by waving my hands at the rain and, guess what? The rain has stopped!  Though that could have been coincidence of course.

Statements such as ''Nature can not be manipulated by human hands'' are just emotional semantics from the deniers. At the other end of the scale, they have even claimed that humans are part of nature, therefore all warming is natural; so desperate they can be to try to downplay human involvement.  Absurd I know but, honestly, I didn't make that up!  

Maybe human hands on their own don't manipulate nature, but drive them to work, warm them by the fire, grow food to sustain them, extract the fossil fuels to power all of the above; that is what is having a cumulative effect.

The rain has started again by the way ...

Farming is just a endeavor, nature will take its course regardless, the word nature is taken from natural, though farming may effect the environment it will not change the natural order of life. You need to think a lot deeper than you are.

Yeah, which is why the Aral Sea is just as deep as always, with a vibrant fishing industry.  Because diverting its supply to grow cotton didn't dry it out and kill all the fish.

I mean, it's obvious that the Aralkum Desert is a myth.

Of course it can. Apart from farming there's all sorts of ways of manipulating and altering nature.  Genetic engineering, farming, even putting up a fence will alter it.  And if that's not enough, global thermonuclear warfare will definitely alter nature.  EDIT:  Yes, farming has had a massive and severely detrimental impact on the entire ecology of this planet.  If you look at Google Earth you'll see that a huge proportion of the Earth's surface is now farmland, very little remains of the natural world.  Nature really doesn't have much of a chance now, not unless there's a serious pandemic that wipes out almost all of humanity.  Even that would only give it a break, we'd soon be back to our present numbers even if it killed 999 out of every 1000.