In the interest of clarifying this a bit.
A Study has the purpose of acquiring knowledge. Many areas of science are fields of study. Nearly everything NASA does is a study. NASA may conduct the occasional experiment, but 98%-99% of what they do is for the specific goal of acquiring knowledge, studying the solar system and universe. The importance of study should not be underestimated. Many fields in science are studied but not experimented on. Astronomy for one. Geology is another one. Some fields of biology and ecology aren't good for experimental testing, but are still studied.
An Experiment, under proper control has enough test subjects to overcome any numerical coincidence in the outcome, and a set of fixed criteria with one specific thing changed.
We can't run true experiments on climate change in the classical experiment sense because we have only one Earth. We'd need at least two identical Earths to run a proper experiment, and ideally, many more than two. That's obviously impossible.
A Research Study can be an experiment or incorporate one or more experiments, but it also, often isn't an experiment. While an experiment is generally quite specific, a research study can be more broad. What your question seems to be asking is about research studies, not experiments. A good research study leaves an equal chance of either a "yes" and a "no" outcome.
Bias research is possible, so lets get that out of the way. Unbiased research leaves the outcome entirely and fairly up to the results of the study. Now, a scientist can still have one outcome in mind. He can even intend to prove something, but that intention doesn't guarantee bias, so long as the study is well outlined and fair.
Climate change has been subject to numerous research studies. I'll list a few. My list below is far from complete.
Measure heat in/heat out from space is a basic one. Satalites measure the heat coming off the earth and the heat coming from the sun. Changes in heat in/heat out are compared to temperature changes on Earth. This is a very basic study that could go either way. It supported greenhouse gas driven climate change.
Temperature change day vs night. If it's the grenhouse gas, then nights should warm faster than days. This was studied and nights did warm faster than days. Another study that supported the greenhouse gas theory.
The cosmic ray/cloud formation theory. That cosmic rays could indirectly heat the earth by cloud formation sounded nuts, but it's actually as good a theory as any and it was studied, at CERN no less. This study had some merit, but it's insufficient to explain the current warming.
Urban Heat Island. In what I consider a hilarious bit of failure, the Koch brothers' funded Berkeley Earth Study was designed specifically to avoid any Urban Heat Island warming and disprove climate change. As I said above, agenda driven research is fine, so long as the research fairly allows the undesired outcome. Well, that's exactly what their study gave them. Their research, designed specifically to debunk man made climate change theory produced results that the Earth is warming even faster than NASA's and the IPCC's results.
Studying heat at different altitudes. Again, if it's the greenhouse gas, more warming should occur lower in the atmosphere, less as you gain altitude. This is exactly what the study found. The high altitude temperature readings from UAH and RSS actually support, they don't dispute greenhouse gas driven climate change.
Any one of these research studies could have made a case for or against. Every one of them, and every research study I've ever read about has supported the man made climate change theory.
Climate change has so much attention, that lots of research has been done. This isn't a case of one study that everyone agrees with, without proper cross-checking. It's been tested a dozen different ways a dozen different times and gone over by thousands of scientists and skeptics. Many studies have been done with the intent to disprove it too. There's a lot of special interest money out there to oppose the theory and they've failed to provide a single good research study that backs up their alternative theory claim. There's not one study that produced results against the prevailing theory and many studies in favor. That's science, not bias.