By Kate Abnett and Alison Withers DUBAI (Reuters) – It’s the issue at the core of COP28: will this year’s U.N. climate talks, held in major oil producer the United Arab Emirates, produce the first global agreement to phase out fossil fuel use? Burning fossil fuels for energy is by far the biggest cause of climate change. It is also the engine of modern life – even with the growth of renewables, fossil fuels produce around 80% of the world’s energy. U.N. climate negotiations over the last three decades, however, have yet to address the issue head on. The COP26 summit in Glasgow in 2021 made the…