What are we doing about climate change?

While nations wrangle over a new global treaty on climate change, the question on many minds is: What happens next?

Key portions of the Kyoto Protocol are set to expire at the end of 2012. But many of the world's major greenhouse gas emitters have already set national targets to reduce emissions, and they're forging their own initiatives to meet those goals.

Some are focusing on curbing deforestation and boosting renewable energy sources. Several nations are experimenting with cap-and-trade plans: Regulators set mandatory limits on industrial emissions, but companies that exceed those "caps" can buy permits to emit from companies that have allowances to spare. In some cases, it's not clear that countries are doing much to meet their stated climate goals. What is clear is that the pledges currently on the table aren't legally binding, and they fall far short of what would be required to stabilize the planet's atmosphere.

Here's a look at what nations are doing:

Australia

Australia has set a national goal of reducing greenhouse gas emissions by 5 percent below 2000 levels by 2020.

Australia didn't sign onto the Kyoto Protocol until 2007, after its Labor Party took control of government, reversing the previous administration's policy. Under the climate pact, Australia agreed to hold the growth in its greenhouse gas emissions to 8 percent above 1990 levels for the 2008-2012 period. By and large, Australia has met those targets, mostly by reducing deforestation and land clearing.

In November 2011, Australian lawmakers approved an ambitious carbon trading plan — the world's largest outside of Europe. Under the plan, Australia's 500 worst polluters would be forced to pay a tax on every ton of carbon they emit starting in July 2012. By 2015, the nation plans to move to a full-on, market-based carbon trading system. Australia says it plans to link its carbon market to one set up in neighboring New Zealand. That might make it harder to dismantle the market if conservatives win back control of Australia's government in 2013.

Brazil

Brazil is aiming to reduce its emissions to 1994 levels and cut deforestation by 80 percent from historic highs by 2020.

Brazil's National Climate Change Plan is focused on expanding renewable electric energy sources and beefing up the use of biofuels in the transportation industry. The country is also focusing heavily on reducing deforestation rates: It's hoping to eliminate illegal deforestation and bring the net loss of forest coverage to zero by 2015.

But a proposal to loosen Brazil's deforestation rules is currently making its way through the legislature. If enacted, critics say the changes could create more opportunities for logging.

Canada

When Canada signed onto the Kyoto Protocol, it committed to reducing its greenhouse gas emissions by 6 percent below 1990 levels. It later proposed a new, less ambitious goal to reduce emissions by 17 percent from 2005 levels by 2020, a pledge that matches the U.S.

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