The size and scope of actions necessary to address climate change can cause paralysis and inaction. In the absence of public policy, emissions would grow to around 60 billion metric tons of carbon dioxide by the middle of this century from current emissions of roughly 30 billion metric tons per year. In order to achieve climate stabilization, most analysis recommends an emission reduction target of 50% to 100% by 2050 from today's levels. Politically, there has been progress. The United States House of Representatives recently passed the climate and energy bill, known as the American Clean Energy and Security Act. The incredible difference between the do-nothing, status quo trajectory and these targets can be daunting. This month on EarthTrends we will give an overview of the most commonly discussed technologies and practices that get us from here to there as well as a consideration of the associated costs of implementing these solutions.

Energy, has powered human development from the dawn of time. The energy from the sun fuels all life on Earth. The potential energy extracted from humans and animals forms the foundations on which our society has been built. The electrical and mechanical energy generated from natural resources such as fossil fuels, water, and steam have opened numerous avenues within industry, transportation and livelihoods. As science and technology progress and energy sources increase in efficiency and capacity so too do the limits of our capabilities.

However, just as energy has the potential to instigate development it can also act as one of the greatest barriers. While the poor can most benefit from improved access to energy sources, they are also the most likely to suffer from the effects of unsustainable energy use such as climate change, deforestation, adverse health impacts and desertification.

Sustainable development supports the concept of lifting populations out of poverty without endangering resources and the environment for future generations. A wide range of past projects have attempted to achieve these objectives, but the United Nations Millennium Declaration in 2000 established for the first time an extensive partnership among nations to reduce global poverty through a specified framework of time-bound objectives. These goals and objectives, which are to be met by 2015, were agreed upon by 189 nations and have come to be known as the Millennium Development Goals (MDGs) (Table 1).

This year marks the halfway point in efforts to achieve the MDGs, and progress has been promising in some areas such as primary education and vaccination rates. However, demographic trends are interfering with efforts to achieve other goals. For example, increasing population exacerbates extreme poverty even as work is being done to mitigate it. Organizations such as the Center for Global Development (CGD) have recognized this impediment. Last month, CGD launched an initiative that calls for more adequate consideration of demographics in the formation of development policy.

The hazy skies over the 2008 Summer Olympics have placed Beijing's air quality at the top of news headlines for more than a month. However, outdoor air pollution, whether in the form of visible haze or invisible ozone and carbon monoxide, is a problem in nearly every country in the world.

As world food prices reach record highs, concerns over agricultural productivity are mounting. Productivity growth has stagnated as the world’s population has continued to rise, and the wealth generated from economic development is further increasing demand for food. The use of food crops like corn and sugarcane for biofuels production exacerbates the situation. The United Nations estimates that agricultural output will have to rise 50 percent by 2030 to meet this increased demand

EarthTrends April 2008 Monthly Update

Before climate change dominated the environmental agenda, deforestation was a central concern for many reasons besides carbon. Forests contain 70 percent of the world's biodiversity, provide vital ecosystem services such as flood control and soil protection, and support the subsistence livelihoods of up to 300 million people, most of whom are poor. To date, efforts to combat deforestation have failed to stop rapid global forest loss, despite some localized successes. Between 2000 and 2005, roughly 13 million hectares of forest disappeared each year, with the largest losses occurring in the biologically rich tropical forests of the developing world (FAO, 2005).

The threat of climate change has created a new imperative--and renewed hope--to protect the values and services rendered by tropical forests. The Intergovernmental Panel on Climate Change (2007) estimates that deforestation contributes 15-20 percent of global greenhouse gas emissions (see Figure 1), yet the forestry sector was largely excluded from the Kyoto Protocol's first commitment period. With negotiations underway for a post-Kyoto agreement set to start after 2012, reduced emissions from deforestation in developing countries, popularly known as REDD, has emerged as a key issue.

Now home to half of the world's people, cities are increasingly at the forefront of our most pressing environmental challenges. While the current pace of urbanization is not unique in human history, the sheer magnitude of urban growth--driven by massive demographic shifts in the developing world--is unprecedented, with vast implications for human well-being and the environment. However, where cities pose environmental problems, they also offer solutions. As hotspots of consumption, production, and waste generation, cities possess unparalleled potential to increase the energy efficiency and sustainability of society as a whole.

In the last quarter century, China's breakneck economic growth has lifted over 50 million people out of poverty and tripled energy demand. Experts predict that China will surpass the United States to become the world's largest consumer of energy and fossil fuels soon after 2010. And because of its heavy reliance on coal, China already emits more carbon dioxide than any country on earth.

The rate and path of this energy growth is of enormous consequence for both China and the world. At stake are issues of global importance, including climate change and competition over dwindling oil resources. Perhaps more important for China, however, are domestic concerns such as severe urban air pollution, energy security, and sustained economic growth.

Global water consumption increased sixfold in the last century--more than twice the rate of population growth--and will continue growing rapidly in coming decades. Yet readily available freshwater is a finite resource, equivalent to less than one percent of the water on Earth. What's more, water and populations are unevenly distributed across the globe; arid and semi-arid regions receive only two percent of all surface runoff yet account for 40 percent of the global land area and house half of the world's poor. Finally, our existing freshwater resources are under heavy threat from overexploitation, pollution, and climate change. Given these trends, equitably providing adequate water resources for agriculture, industry and human consumption poses one of the greatest challenges of the 21st century.

Indoor air pollution causes 1.6 million premature deaths every year and afflicts nearly half of the world's population, predominantly the rural poor. This makes it the second leading environmental health threat in the world and a critical barrier to poverty alleviation in low-income countries. Yet this issue is rarely discussed outside of public health circles, probably because the health consequences of indoor air pollution are not immediate and can be difficult to trace. Thus, indoor air pollution remains a quiet and neglected killer, with lack of global awareness being one of the primary obstacles to the widespread implementation of existing, proven interventions.