The northward expansion of these ticks has been linked to climate change, but the problem is not limited to Lyme disease. According to experts, the rapid warming of the Earth — which is explicitly linked to human dependence on fossil fuels — can increase the reproduction rates of bacteria and viruses like malaria and dengue, as well as the biting rates of the vectors that transmit them. Extreme weather events, intensified by climate change, produce conditions ripe for diarrheal diseases.