The ability to inventory and map soil salinity at regional scales remains a significant challenge to scientists concerned with the salinization of agricultural soils throughout the world. Previous attempts to use satellite or aerial imagery to assess soil salinity have found limited success in part because of the inability of methods to isolate the effects of soil salinity on vegetative growth from other factors. This study evaluated the use of Moderate Resolution Imaging Spectroradiometer (MODIS) imagery in conjunction with directed soil sampling to assess and map soil salinity at a regional scale (i.e., 10-105 km2) in a parsimonious manner. Correlations with three soil salinity ground truth datasets differing in scale were made in Kittson County within the Red River Valley (RRV) of North Dakota and Minnesota, an area where soil salinity assessment is a top priority for the Natural Resource Conservation Service (NRCS). Multi-year MODIS imagery was used to mitigate the influence of temporally dynamic factors such as weather, pests, disease, and management influences. The average of the MODIS enhanced vegetation index (EVI) for a 7-yr period exhibited a strong relationship with soil salinity in all three datasets, and outperformed the normalized difference vegetation index (NDVI). One-third to one-half of the spatial variability in soil salinity could be captured by measuring average MODIS EVI and whether the land qualified for the Conservation Reserve Program (a USDA program that sets aside marginally productive land based on conservation principles). The approach has the practical simplicity to allow broad application in areas where limited resources are available for salinity assessment.

In the 21st century, mapping and monitoring the occurrence of soil degradation will be an important component of successful land management. Remote sensing, with its unique ability to measure across space and time, will be an increasingly indispensible tool for assessing degradation. However, much of the recent experience and progress in using remote sensing and other geospatial technologies to map soil degradation is reported outside of the peer-reviewed literature. This motivated the organization of a special collection of papers focused on remote sensing of soil degradation, to highlight recent successes, common challenges, and promising new approaches. This introductory paper provides an overview of the papers, gaps in knowledge, and future research directions. Across several regions and types of degradation, many assessments to date have relied heavily on data from the Landsat satellite sensor. Many approaches have also relied at some point on subjective visual interpretation, either of the satellite imagery itself or to provide field data used to train models that use satellite data. While subjectivity is not necessarily bad, it precludes repeatability and makes it even more important to rigorously test model estimates with independent data. Overall, it remains quite challenging to find robust relationships between remote sensing measures and soil degradation, particularly for slight to moderate levels of degradation. There have nonetheless been some clear successes, and there remains great potential for progress. Promising directions outlined in the papers include using multi-year measures of vegetation condition, combining different sensor systems including optical and radar data, and using advanced statistical techniques such as Bayesian networks and decision trees.

The ongoing expansion of oil palm plantations in the humid tropics, especially in Southeast Asia, is generating considerable concern and debate. Amid industry and environmental campaigners' claims, it can be hard to perceive reality. Is oil palm a valuable route to sustainable development or a costly road to environmental ruin? Inevitably, any answer depends on many choices. But do decision makers have the information they require to avoid pitfalls and make the best decisions? This review examines what we know and what we don't know about oil palm developments. Our sources include academic publications and ‘grey' literature, along with expert consultations. Some facts are indisputable: among these are that oil palm is highly productive and commercially profitable at large scales, and that palm oil demand is rising. Implementing oil palm developments involves many tradeoffs. Oil palm's considerable profitability offers wealth and development where wealth and development are needed-but also threatens traditional livelihoods. It offers a route out of poverty, while also making people vulnerable to exploitation, misinformation and market instabilities. It threatens rich biological diversity-while also offering the finance needed to protect forest. It offers a renewable source of fuel, but also threatens to increase global carbon emissions. We remain uncertain of the full implications of current choices. How can local, regional and international benefits be increased while costs are minimised? While much important information is available, it is often open to question or hard to generalise. We conclude this review with a list of pressing questions requiring further investigation. Credible, unbiased research on these issues will move the discussion and practice forward.

After North Korea’s nuclear test on 9 October 2006, the fate of South Korea’s engagement policy with North Korea seemed to hang in the balance. To many, the nuclear test stood as a clear indictment of the Sunshine Policy and its successor, President Roh Moo-hyun’s Peace and Prosperity Policy. After years of investment and aid to the North under these policies, South Korea appeared to have received little in return. Conservative lawmakers charged that the nuclear test amounted to the “death penalty” for the Sunshine Policy, and former president Kim Young-sam proclaimed that the policy “should be thrown into a trash can.” Roh’s unification minister apologized to the National Assembly.

But others did not see the nuclear test as a verdict on South Korean engagement of the North. To more progressive forces, including the Roh administration, this is not a story of inter-Korean cause and effect; engagement represents a much larger inter- Korean effort, while the nuclear issue is rooted in problematic U.S.-DPRK relations. In their view, the nuclear test occurred because the Bush administration has taken a hard line with North Korea, creating an environment—featuring “regime change” rhetoric and the preemptive-strike doctrine—that spurred the North to pursue weapons considered the ultimate guarantee of security. The Sunshine Policy cannot be held to account for ruinous U.S.-DPRK relations, though such a circumstance can hinder inter-Korean engagement. While Roh offered a careful, politically calibrated suggestion to the public in the wake of the nuclear test, saying he “would like to suggest that we take time to figure out the causal relationship between the engagement policy and the nuclear test,” former president Kim Dae-jung pressed the progressive perspective in no uncertain terms, offering a direct, clamant answer: “North Korea has never said it would develop nuclear weapons because of South Korea’s Sunshine Policy. It said that it was developing nuclear weapons as a last resort to survive, because the United States was hard on the country.”

Presentation from the session session "Biofuels, Tropical Deforestation, and Climate Policy: Key Challenges and Opportunities" at the annual AAAS meeting, Feb 14 2009.