Food Industry Issues Warning On Global Warming

I've discussed this in a previous post about the great danger of mass starvation in the next thirty years.  Now the food industry is joining in.

Leaders from the food industry issued a warning to Congress recently, telling elected politicians to take action on climate change or face a global food shortage.  Leaders from companies such as Kellogg’s, General Mills, Nestle, Mars, and many others co-signed a letter published in The Washington Post, where they warned about the threats that climate change poses to the food industry.

From the letter:
By  2050, it is estimated that the world’s population will exceed nine billion, with two-thirds of all people living in urban areas. This increase in population and urbanization will require more water, energy and food, all of which are compromised by warming temperatures.

The challenge presented by climate change will require all of us – government, civil society and business – to do more with less. For companies like ours, that means producing more food on less land using fewer natural resources. If we don’t take action now, we risk not only today’s livelihoods, but also those of future generations.

These are not "alarmist" companies.  What will it really take to get the attention of the members of Congress who deny global warming?