Whether or not there is link between old age and contrarianism/denial is an open question. My guess is that there is a stronger correlation with other factors, including education attainment, pre-existing political and cultural beliefs, and immediate life experience and expectations.
But clearly we need more than that.
On the question of how to confront the growth of contrarianism/denial in the face of even more compelling scientific evidence, one place to start could be IPPR's recent document Consumer Power: A Communications Guide for Mainstreaming Lower-Carbon Behaviour. Its checklist goes:
1. “Don’t focus on climate change"
2. “Focus on saving money now”
3. “Prevent the rebound effect” (in which people spend money saved through low-carbon behaviours on other, high-carbon practices)
4. “Talk about carbon pollution, not CO2 emissions”
5. “Satirise high-carbon behaviours”
6. “Make lower-carbon options desirable”
7. “Remember that being in control matters” (e.g. with regard to controlling personal energy costs)
8. “Make it fun”
9. “Avoid guilt and the ‘environmental’ label”
10. “Use messengers that ‘keep it real’”