| You can definitely lose weight no doubt about it. It's all about calories in and calories out.
However, if you stick solely to cardio then you will also lose muscle as well as fat. You want to retain as much muscle as possible as it drastically aids in further fat loss.
I would still recommend you do some sort of resistance training. You dont even need equipment.....use your own body weight and get creative if need be i.e. use heavy backpacks etc....
Squats, pushups, pull/chinups and their variations are all great exercises that don't necessarily require any weights or equipment.
With your cardio, if you are running for 30 mins at a constant pace, try mixing it up a little by jogging, fast jogging, sprinting and even walking some sections. It is much more effective than keeping a constant pace. There is heaps of information on this type of interval training on the forum. | 
