Accounting for more than 40 percent of the world's greenhouse gas emissions, the United States and China should work together to prevent runaway climate change and demonstrate to the world sustainable, low-carbon development models. As emissions around the world continue to increase, collaboration between the two countries in key areas such as energy efficiency and clean energy is essential to stabilize the Earth's climate.

The US and China should use the ongoing UN climate change conference in Cancun, Mexico, to re-affirm their commitment to addressing their domestic emissions and improving reporting and transparency on their domestic actions. They should take steps to become a model for international collaboration in the pursuit of low-carbon solutions and the resulting economic, social and environmental benefits.

Having worked in China for the last 15 years on projects to improve the efficiency of China's industries and buildings, and develop clean energy, our organization, the Natural Resources Defense Council (NRDC), has witnessed first-hand the surge in recent years in national and local policies to adopt efficient, low-carbon technologies.

Textile mills consume and pollute as much as 200 tons of water to make one ton of fabric, and emit considerable volume of carbon dioxide (CO2). The NRDC's "responsible sourcing initiative" techniques not only reduce water pollution and energy use, but also help textile mills run more efficiently and use fewer resources, saving companies significant amount of money.

If just 100 small- to medium-sized textile mills implement our recommended improvements, China would save more than 16 million tons of water a year, enough to provide 12.4 million people with drinking water for a year. The practices can also eliminate nearly 1 million tons of CO2 a year, about the same volume that 172,000 cars emit in one year.

In November 2009, President Hu Jintao and US President Barack Obama strengthened China-US collaboration on clean energy through a broad set of initiatives, including the establishment of a joint Clean Energy Research Center, which will focus initially on building efficiency, carbon capture and storage, and electric vehicles (NRDC is a member of the building efficiency consortium).

The US-China clean energy initiatives, no doubt, will be fruitful and have meaningful economic and environmental impacts far beyond the investments that each country makes.

Despite its significant efforts and achievements in improving energy efficiency and addressing its emissions over the last five years, China has not always got the recognition it deserves. This in part is because other countries do not understand the significant steps that China has been taking to fight climate change, and in part because of the relative lack of transparency of China's energy use and emissions.

The compromise that China and the US reached at the Copenhagen climate conference last year requires developing countries to increase the frequency of their reporting on mitigation actions and emission inventories to every two years, bringing them more in line with the reporting requirements of developed countries. This should help increase mutual understanding and trust among countries, and assure them that each is doing its part to fight climate change.

China faces significant challenges on the domestic front, too. The target responsibility system for evaluating the performance of provincial and local officials in meeting their energy and major pollutant emission reduction targets provides a strong incentive for officials to pursue environmental and climate objectives alongside economic development goals. Yet ensuring the quality of data in this process is an acknowledged challenge.

Over the last few years, China has begun disclosing a wider range of energy efficiency performance data, lists of outdated facilities that must be removed from use and other information in the service of achieving its environmental and energy targets.

But not much else is known about the systems of review that China is using to evaluate the quality of this information and to verify the performance of lower-level officials. Broadening the public disclosure of information and strengthening the domestic system for data review will enhance China's ability to meet its targets and move forward with its domestic agenda.

Improving the transparency of every country's actions to fight climate change and reduce emissions is no trivial issue. By increasing the frequency and depth of reporting its actions and emissions, China can provide a useful model for other developing countries and get the international recognition it deserves.

As part of the Copenhagen Accord reached last December, countries accounting for more than 80 percent of global greenhouse gas emissions have already committed to undertaking specific actions to fight climate change. The Cancun conference needs to re-affirm these pledges and countries should be prepared to report on their progress in implementing these actions over the past year.

Developed countries should be prepared to show substantive progress on the other key agreement reached in Copenhagen - finance for developing countries to adapt to and fight climate change, use of clean energy and reduction in deforestation. The $30 billion in prompt-start funds pledged by developed countries last year must be turned into real money to lead to meaningful actions on the ground.

The two linchpins of a future climate agreement - greater transparency on actions and emissions, and increased financing for developing countries - are interdependent in the negotiations. It is unlikely for one to move forward without progress being made on the other.

Specifically, developed countries and developing countries both should be subject to greater transparency, though the exact form will vary from one country to another. Countries should also agree on the details of the global fund envisioned at Copenhagen. Such a fund, if properly implemented, could help mobilize and implement the ramp-up in climate funding that the Copenhagen Accord calls for. Interim reporting guidelines and a common reporting format for prompt-start funding should be created to build trust and ensure transparency around climate finance.

China and the US can come up with constructive ways to address differences on key issues and show the world how moving toward a low-carbon economy is in every country's interest. Both countries will benefit from tapping into the growing demand for clean energy and both will benefit by ensuring that the worst impacts of climate change are avoided.

The two countries have never been more dependent on each other to achieve their climate and energy priorities, and to ensure the health and well-being of their peoples.

Barbara Finamore is China program director of the Natural Resources Defense Council and Jake Schmidt is its international climate policy director.