Climate change - which the United Nations defines as long-term shifts in temperatures and weather patterns - is a growing global problem, particularly for farmers. A recent UN report found agricultural productivity growth in Africa has decreased by 34 percent since 1961. That's more than any other region in the world.Michael Kaloki takes a road trip around Kenya, speaking to farmers about their struggles to grow crops with the increasingly unpredictable weather. He asks Rachel Bezner Kerr, a professor at the Department of Global Development at Cornell University in the United States why climate change is happening and what the future holds.He visits the organisations that are trying to help farmers adapt to climate change. Dr Ivan Rwomushana, from the non-profit inter-governmental organisation CABI, and Oliver Furechi from the charity Practical Action tell him what strategies and solutions they're teaching farmers.Presenter: Michael Kaloki Producer: Jo CritcherImage: Nancy, a farmer in the county of Nakuru in Kenya; Credit: BBC