Climate change is adversely affecting bumblebees and it is harming them and their homes more so than pesticides. Like other insects, bumblebees are not moving to cooler climates. Butterflies, in contrast, will migrate to greater elevations or farther from the equator when their native location becomes too hot. Bumblebees leaving their homes when it’s too warm outside, yet they appear to be displaced rather relocated. 
Extensive losses of pollinators due to climate change are diminishing food security and our global economy. We can improve the outlook for pollinators at continental scales by reducing the rate of climate change. It is now proven it’s just too hot and that pesticide use or habitat loss is not just the main reason for the widespread, rapid declines of pollinators across continents. Action now against global warming is the only way to preserve species like bumblebees for the future. http://www.delta-optimist.com/opinion/blogs/deltabc-1.983313/blog-bumblebees-hate-heat-over-pesticides-1.1998601