Get to Tate Modern for 4pm today if you want to support a major new campaign to curb greenhouse gas emissions. The 10:10 initiative aims to squeeze emissions by 10% in 2010, hence the scripture-esque '10:10' moniker. The former power station seems an apt place to begin such a laudable campaign. It's also big enough to support live performances from Reverend and the Makers and Stornoway, while hoards of climate savvy locals flock to take part. If the lure of free music and, well, saving the planet isn't enough, there's also a free glass of bubbly for the first 1010 people who turn up. Stick around till 6.30 for a 1010 megapixel group portrait of everyone who turns up. Whether numerological playfulness and champagne bribery will translate into direct and effective action on behalf of individual signatories to the 10:10 charter remains to be seen. But with a giant glass biome of large organisations already signed up, including the Guardian, Tottenham Hotspurs and the NHS, this could be one green initiative that actually goes somewhere.