We’ve been gazing at the skies for thousands of years and have captured our amazement in beautiful verse. But what mechanisms create those wonderful cloudy heavens? If it were up to cloud professor Herman Russchenberg: 'We would study the linkages between climate, biodiversity and mitigation measures.'
By Rob Buiter
How do clouds relate to climate?
'Without clouds, temperatures on Earth would be about 6 or 7 degrees higher.' Clouds reflect sunlight, keeping us relatively cool. More precisely, they used to keep us cool, as things have changed since we started pumping greenhouse gases into the atmosphere. The cooling effect of cloud cover is demonstrably diminishing, even though we don’t quite understand the exact underlying.'
'We will need to study clouds from all sides to find out: using satellites from above and radar from below, as well as lasers and radiation meters to study clouds from the inside. Are clouds becoming less reflective? Are they becoming an insulating blanket of sorts? Those are the questions we want to answer by studying clouds in greater depth than ever before.'
How relevant is your climate research to biodiversity research?
'All climate research is directly relevant to biodiversity! Global changes in temperature, precipitation, wind, as well as the acidification of the oceans have direct effects on everything from plant growing seasons to animal migration patterns. This link between climate and biodiversity becomes as clear as day at the regional or even local scale.'
'That is why we do not only study the large-scale effects of cloud cover at Delft, but also try to understand the local difference between the climate over a bare patch of sand, a grassy plain, a forest or in a city. We need to think smaller to understand the concrete effects of climate on biodiversity.'
Are the effects of local climate mitigation measures on biodiversity also so obvious?
'Not at all. At the level of individual nature reserves, polders or cities, the effects are a lot less obvious. Take the Urban Heat Island effect, for example, which sees highly built up urban areas get a lot warmer in summer than the surrounding area. An ostensibly sensible climate adaptation measure might be to paint all houses white to stop them absorbing solar heat.'
'If you do the math, however, you realise that this may actually only make the streets between those houses hotter, endangering the already vulnerable urban green spaces. The link to biodiversity becomes even more evident in adaptations to combat flooding. Large water basins to collect rainwater, for example, also attract mosquitoes and may therefore affect the spread of disease.'
The effects of climate mitigation need to be factored in from the word go.'
How do you compare climate apples with biodiversity oranges?
'Climate change mitigation measures, also known as climate adaptation, will have to be studied alongside their effects on biodiversity. Currently, the impacts of offshore wind farms on marine life or solar farms on nearby meadows are treated as secondary considerations.'
'Birds that meet their end by colliding with the blades of a wind turbine are seen as unavoidable collateral damage as we pursue a higher goal: wind energy. I advocate a more comprehensive approach, in which the effects of climate mitigation measures on biodiversity are factored into the planning process from the word go.'
That will hardly make climate policy any easier. Are you optimistic about achieving the climate commitments made in 2015?
'Frankly, I don’t think we’re going to meet the Paris targets, or 1.5 to up to 2 degrees of warming. I’m afraid there will be no way out until we have no way out. No matter what we come up with in our West-European paradise, it will all come to naught if we don’t help countries in Africa and Asia get started on a sustainable transition to greater prosperity.'
Tinkering with the climate can kindle all sorts of political conflict.'
Besides preventing and adapting to the effects of climate change, do you see any benefit in climate engineering?
'Should things really get out of hand, we could start influencing cloud formation by dispersing particles into the air. We’re also working out how to have wind turbines atomise seawater in order to cool coastal areas. But don't get me wrong: these are all last-resort precautions that you want to have just in case, but would preferably leave unused. Tinkering with the climate can kindle all sorts of political conflict and change biodiversity patterns to boot. The best solution - for climate and biodiversity - is to reduce greenhouse gas emissions.'
Herman Russchenberg is Professor of Atmospheric Remote Sensing at TU Delft and director of the TU Delft Climate Institute. His research explores how clouds, rain and small particles in the air affect the climate system.
New white paper 'Connect Climate and Biodiversity for Society, Economy and Nature'
This article is from the new white paper 'Connect Climate and Biodiversity for society, economy and nature' of Leiden-Delft-Erasmus Universities. In this paper, scientists, foresters, bankers, farmers, and municipal officials advocate protection of eco-systems as a strategy against global warming.
Download the white paper (written in Dutch, except the English summary and list of recommendations) or order a copy via Katja Hoiting: k.hoiting@tudelft.nl
