SciDev.Net

This report, written by a team of international scientists and published by the UN Environment Programme (UNEP), explores the effects of 'atmospheric brown clouds'(ABCs) on regional climate, agriculture and human health.

ABCs are large plumes of pollutant gases that result from burning fossil fuels and biomass. The authors of the UNEP report examine the spread of ABCs — particularly in Asia — and discuss their likely impacts, including decreases in the Indian summer monsoon rainfall, accelerated glacial retreat and increases in surface ozone.

They suggest that ABCs threaten water and food security in Asia, impact human health and may mask the warming effects of climate change by 20 – 80 per cent. The authors recommend an international response to tackle the twin effects of ABCs and greenhouse gases, and the unsustainable development that underpins them.

This independent review, commissioned by the UK chancellor of the exchequer, examines the economic impacts of climate change, the economics of stabilising greenhouse gas emissions and considers policymaker's challenges in adapting to climate change and moving towards a low-carbon economy.

The review uses scientific evidence to highlight the risk of irreversible climate change impacts in normal emission scenarios. Evidence of threats to the basic elements of life around the world, including access to water, food production and health are presented, with poorest countries projected to suffer the most.

The review also shows that, left unabated, climate change will damage economic growth. Mitigating climate change effects must be seen as an investment. Moving towards a low-carbon economy may have a significant cost and challenge competitiveness, but it will also bring opportunities for growth.

In discussing the policy challenges for reducing emissions, the review emphasises the need for strong international cooperation and collective action. Climate change policy, says the author, will need to focus on carbon pricing, low-carbon technology, and the removal of barriers to behavioural change across the world. Developing countries in particular will need carbon finance to support emission reductions and curb deforestation, as well as international aid to implement adaptation efforts.

Worldwide, greenhouse gas emissions are rising faster in transportation than in any other sector. Rapid motorisation — more cars and trucks — is the principal cause. This report focuses on the challenges faced by developing countries in accommodating and managing motorisation and the demand for improved transportation.

The report provides a broad characterisation of transportation in developing countries, identifying common challenges and opportunities for policymakers, and suggesting policy options that aim to slow the growth of greenhouse gas emissions from the transportation sector.

The most important observations are:

• Rapid motorisation — and rapid growth in transport-related greenhouse gas emissions — are unavoidable in most developing nations.
• The relationship between car ownership and income is not fixed.
• Once people have personal vehicles, they use them even if alternative transportation modes are available.
• There are many sensible policies and strategies that would slow the growth of transportation sector greenhouse gas emissions. Key strategies include increasing the cost of using conventional private cars and enhancing the quality and choices of alternative transportation.
• Many of the strategies for slowing and eventually reducing greenhouse gas emissions from transportation have local as well as global benefits.