One of the benefits of organic farming is supposed to be the use of organic fertilizers, as opposed to the nitrogen based fertilizers used in conventional agriculture. This would imply that organic farming would not be contributing to the process of climate change. But this piece at Biofortified.org explains that the issue of how the manure (used as fertilizer in organic farming) was actually produced. If it came from conventionally raised animals then it is part of the same process as the nitrogen fertilizer used on conventional farms and very much a part of the climate change process. As always, these issues are not either/or ones and the need for nuance in discussions is essential. The whole issue is very well explained here.