Miranda Kerr is back for the second year running as the Global Ambasssador for Earth Hour — and this time, she's bringing yoga. 


The "lights out" campaign, which last year featured participation by more than 135 countries and hundreds of millions of people, is trying something different this year with a "I will if you will" challenge. Examples include "I will plant 20 trees and sing 'Barbie Girl' on YouTube if you will join Earth Hour communities" and "I will jump off a cliff if you eat 50 percent less meat," etc. 


Kerr, a devoted yoga practitioner, decided to host an online class if 500 other people take part in the "I will if you will" dares and upload their challenges to YouTube. So far, 207 have taken her up on the offer — so it's safe to assume she'll be teaching us all the finer points of yoga soon. 


Also on MNN: 9 alternative light sources for Earth Hour


Naturally, Kerr is excited to be involved in this year's campaign once again.


"My childhood helped me appreciate the environment, it also made me understand that we depend on the environment as much as the environment depends on us," she writes on the site's blog. "We are a part of the (universal) ecosystem and every action we take has a positive or negative consequence to the system as a whole."


"Earth Hour is (all) about encouraging positive action, and that is exactly why I have chosen to be involved," she adds. "I believe we can all do our best to make small changes to create positive effects."


To learn more about the 2012 Earth Hour event, jump here


Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Miranda Kerr to host yoga class for Earth Hour
Supermodel once again named Global Earth Hour Ambassador in preparation for the lights-out moment on March 31.