Dr Howden began his research career in 1981 in the New South Wales Soil Conservation Service. He then joined the Queensland Department of Primary Industries as a pasture agronomist in 1987 following completion of his doctorate with CSIRO in Townsville, Queensland.
In 1990 he joined the Bureau of Resource Sciences to lead their Land and Water Section. Dr Howden joined CSIRO in 2000. He has developed the national and international greenhouse gas inventories for Australia's agricultural sector and assessed sustainable methods of reducing greenhouse emissions from agriculture. Dr Howden was a major contributor to the International Panel on Climate Change (IPCC), sharing the 2007 Nobel Peace Prize with other IPCC authors and Mr Al Gore.
Dr Howden has conducted many studies on climate change impacts and adaptation, including studies in:
- cropping and grazing systems
- mixed farming systems
- land use change
- electricity demand
- water resources
- natural resource management
- biodiversity management
He has worked with government and industry policy groups, informing their development of strategic approaches to climate change impacts and adaptation and to sustainable agriculture. He has worked with industry and community groups to assess practical adaptation options for managing climate change impacts and to develop innovative agricultural practices. According to Dr Howden, 'Australian farmers will need to be adaptable to cope with, and even take advantage of, climate change.'