FYI: Green bonds allow fixed income investors to both fulfill their investment objectives and make a positive impact on the environment. With pricing levels between green and conventional bonds generally very close and highly correlated, the investment case for holding green bonds begins with the impetus for holding any fixed income investment: primarily, income and relative safety versus other portfolio holdings.
Regards,
Ted
http://www.etf.com/sections/etf-industry-perspective/vaneck-investment-case-green-bonds?nopaging=1