Scientists question models to analyse impacts of climate change on biodiversity: past predicts species richness better than contemporary climate

Why is life on Earth not evenly distributed? Geographic patterns of species diversity and their underlying processes have intrigued scientists for centuries, and continue to spur scientific debate. Studies carried out over the past 20 years have led to the conclusion that species diversity is best predicted by contemporary distribution patterns of energy and water, the so-called 'contemporary climate' hypothesis.
Because current climate gradients are correlated with past climate variability, it has also been suggested that current climate acts as a surrogate for evolutionary processes that have been triggered by past climate variability, giving rise to the 'historic climate' hypothesis.
Now, new high-resolution data on historic climate have allowed the scientists to finally directly test the 'historic climate' versus 'contemporary climate' hypotheses of biological diversity. Their findings offer a new, illuminating perspective on the debate: contrary to the expectations of many scientists they found that historic climate variability was a better predictor of reptilian and amphibian diversity in Europe than contemporary climate.
The lack of quantitative spatial data on variation in climate over historical time has prevented more rigorous testing of these diverging hypotheses, says Dr. Araújo from the Deptartment of Biodiversity and Evolutionary Biology at Spain's National Museum of Natural Sciences (CSIC). As a consequence, the debate on the causes of diversity gradients has turned to some degree into a discussion of semantics.
But recent developments in general climate models have finally facilitated high resolution predictions of past climates. In collaboration with leading climatologists working on paleoclimate modeling in the United Kingdom, Araújo, Rahbek and colleagues provide the first comparative test capable of differentiating between the contribution of contemporary and historical climate drivers of diversity gradients across a complete lineage of species at a continental scale.
In recent years, analytical attempts to shed light on the role of history in determining today's patterns of species richness have focused on the strong residual variation of models using contemporary climate, explains Dr. Carsten Rahbek from the Center of Macroecology at the University of Copenhagen. It has been argued that these residuals provide information about the role of historical rather than contemporary constraints. However, such an analytical approach assumes that contemporary climate is the main explanatory force. In other words, the contemporary and historical hypotheses are not tested simultaneously in a directly comparable manner, and historical hypotheses are only invoked to explain what is left to elucidate after the implementation of contemporary environmental processes.
Our results are striking in that they contradict previous studies of large-scale patterns of species richness. They provide the first evidence, using a quantitative analytical approach, that historic climate can contribute to current patterns of richness independently of, and at least as much as contemporary climate. - Dr. Carsten Rahbek, Center of Macroecology, University of CopenhagenThe findings have profound implications for the study of diversity on Earth, and challenges the current view that patterns of contemporary climate are sufficient to explain and predict diversity.
The scientists took species data of all European amphibian and reptile species, and projected them on a 50 km European grid (map, click to enlarge):

Three measurements of species richness were used: total number of species per grid cell; number of species per grid cell among the top 50% narrower-ranging species and number of species among the 25% wider-ranging species. The 50% threshold for narrow ranging species was selected because of the highly skewed frequency distribution of range sizes (i.e. most species having narrow range sizes and very few having wide range sizes).
Correlates of species richness were examined using two contemporary climate variables (annual mean temperature and annual total precipitation sum), and two variables reflecting long term climate stability (the anomaly between mean annual temperatures and annual total precipitation sum in the Last Glacial Maximum (LGM) and at present). The model incorporated prognostic cloud, water and ice, had a mass-flux convection scheme with stability closure and used mean orography.
The model was integrated for the LGM over 20 simulated years and climatological means were compiled for the final 14 year. Time-series analysis of various climate variables for the entire 20 year simulation shows that disregarding the first 6 year allows the climatology model to reach full equilibrium.
Importance of past changes
Statistical analyses reveiled spatial correlations which yielded data that surprised the scientists.
They found that both mean contemporary annual temperatures and historic temperature stability between the LGM and the present significantly predict species richness of reptiles and amphibians in Europe. Species richness among reptiles is also significantly correlated with contemporary precipitation, whereas species richness among both reptiles and amphibians is significantly related to 'historic' precipitation stability.
Because contemporary temperature values are highly correlated with historic temperature stability, partial regression analysis was used to partition the effects of contemporary climate (both the energy and water-energy variants) and historic climatic stability.
Variation due to historic climate stability was seen to be greater than variation explained due to factors associated with contemporary climate, despite important shared variance between the two components. These results were consistent with the initial prediction that historic climate changes can take precedence over contemporary climate in explaining current gradients of species richness.
Reptiles and amphibians rely on external warmth to raise their body temperature and become active. Their ability to cope with lower temperatures is limited, and many species find it difficult survive in regions where mean annual temperatures are below freezing. However, despite evidence that contemporary temperature and precipitation exert strong effects on the richness and distributions of individual species of reptiles and amphibians in Europe, the scientists found, in concurrence with their second prediction, that the distribution of narrow ranging species is markedly constrained by the mean annual freezing conditions in the LGM, whereas widespread species are more constrained by current mean annual freezing conditions.
These results thus support the prediction that a large number of widespread species are likely to have large range sizes because they have been able to largely adjust to current climate conditions by means of colonization, while narrow-ranging species are at least partly restricted because of their poor ability to track climate changes.
There are certainly other factors causing rarity among species, but if colonization ability was not limiting the post glacial distribution of species, one would expect that several endemics of southern European alpine and temperate environments would now extend their ranges into central and northern Europe.
Given that there are generally more narrow ranging species than there are wide ranging species and that narrow ranging species are less likely to be at equilibrium with current climate conditions, it is likely that the impact of historic climates on current species richness is a more widespread phenomenon than previously acknowledged by proponents of contemporary climate hypotheses.
However, the scientists also predict that the historic signature on contemporary richness gradients is likely to be reduced among organisms with greater colonization abilities, such as birds and some plants. This prediction is supported by two recent studies that analyzed the impact of contemporary LGM climates on the richness of a selected sample of northeastern Australian endemic fauna and European flora; these studies demonstrated that historic climate was the single best explanatory variable of richness among narrow-ranging low dispersing endemic animals in Australian rainforest as well as narrow-ranging plant species in Europe, whereas contemporary climate was best at explaining richness among wide-ranging and good-disperser species.
Looking to the future
Differentiating between contemporary and historical hypotheses is important, not only for theoretical reasons: an understanding of the mechanisms that generate and maintain diversity provides valuable insights for predicting the impacts of contemporary climate changes on biodiversity.
"If contemporary climate does drive species richness, then current climate variables could be used to accurately predict the effects of climate change on biodiversity. But if, as shown in the study, the mechanisms underlying contemporary patterns of species richness are in fact strongly influenced by the history of climate, then current-climate predictions may be seriously misleading and alternative approaches to predict the effects of climate change on biodiversity must be developed", Dr. Araújo concludes.
Map: Species richness among all (a) European reptile (left) and amphibian (right) species; (b) the top 50% narrow-ranging; and (c) the top 25% wide-ranging species. Species richness scores in each map are divided into thirty three equal-frequency color classes, such that maximum scores are shown in red and minimum scores are shown in blue. The horizontal line through the south of Europe represents the 0°C isotherm during the Last Glacial Maximum (LGM; 21 kya), whereas the line through the north represents the current 0°C isotherm. The paleoclimate simulation used to draw the 0°C isotherm in the LGM is based on the HadAM3 General Circulation Model.
References:
Miguel B. Araújo, David Nogués-Bravo, José Alexandre F. Diniz-Filho, Alan M. Haywood, Paul J. Valdes and Carsten Rahbek, "Quaternary climate changes explain diversity among reptiles and amphibians", Ecography (OnlineEarly Articles), 23 Oct 2007, doi:10.1111/j.2007.0906-7590.05318.x
Eurekalert: Are current projections of climate change-impacts on biodiversity misleading? - November 21, 2007.
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Friday, November 23, 2007
Commission presents European Strategic Energy Technology Plan: towards a low carbon future
The inter-related challenges of climate change, security of energy supply and competitiveness are multifaceted and require a coordinated response. The Commission is piecing together a far-reaching jigsaw of policies and measures: binding targets for 2020 to reduce greenhouse gas emissions by 20% and ensure 20% of renewable energy sources in the EU energy mix; a plan to reduce EU global primary energy use by 20% by 2020; carbon pricing through the Emissions Trading Scheme (EU ETS) and energy taxation; a competitive Internal Energy Market; an international energy policy.
Technology is vital in reaching all the above-mentioned objectives. A dedicated policy to accelerate the development and deployment of cost-effective low carbon technologies is therefor required. To meet the 2020 targets, the EU wants to lower the cost of clean energy and put EU industry at the forefront of the rapidly growing low carbon technology sector. In the longer term, if the EU is to meet the greater ambition of reducing our greenhouse gas emissions by 60-80% by 2050, new generations of technologies have to be developed through breakthrough in research.
The transition to a low carbon economy will take decades and touch every sector of the economy, but we cannot afford to delay action. Decisions taken over the next 10-15 years will have profound consequences for energy security, for climate change, for growth and jobs in Europe.
Key technology challenges for the next 10 years
To achieve the 2050 vision, towards complete decarbonisation, the EU wants to develop a new generation of technologies through major breakthroughs. Even if some of these technologies will have little impact by 2020, it is vital to reinforce efforts today to ensure that they come on-stream as early as possible. The Union also has to plan for major organisational and infrastructure changes.
Key EU technology challenges for the next 10 years to meet the 2020 targets:
- Make second generation biofuels competitive alternatives to fossil fuels, while respecting the sustainability of their production
- Enable commercial use of technologies for CO2 capture, transport and storage through demonstration at industrial scale, including whole system efficiency and advanced research
- Double the power generation capacity of the largest wind turbines, with off-shore wind as the lead application
- Demonstrate commercial readiness of large-scale Photovoltaic (PV) and Concentrated Solar Power
- Enable a single, smart European electricity grid able to accommodate the massive integration of renewable and decentralised energy sources
- Bring to mass market more efficient energy conversion and end-use devices and systems, in buildings, transport and industry, such as poly-generation and fuel cells
- Maintain competitiveness in fission technologies, together with long-term waste management solutions
Key EU technology challenges for the next 10 years to meet the 2050 vision include:- Bring the next generation of renewable energy technologies to market competitiveness
- Achieve a breakthrough in the cost-efficiency of energy storage technologies
- Develop the technologies and create the conditions to enable industry to commercialise hydrogen fuel cell vehicles
- Complete the preparations for the demonstration of a new generation (Gen-IV) of fission reactors for increased sustainability
- Complete the construction of the ITER fusion facility and ensure early industry participation in the preparation of demonstration actions
- Elaborate alternative visions and transition strategies towards the development of the Trans-European energy networks and other systems necessary to support the low carbon economy of the future
- Achieve breakthroughs in enabling research for energy efficiency: e.g. materials, nano-science, information and communication technologies, bio-science and computation.
Since the oil price shocks in the 70s and 80s, Europe has enjoyed inexpensive and plentiful energy supplies. The easy availability of resources, no carbon constraints and the commercial imperatives of market forces have not only left us dependent on fossil fuels, but have also tempered the interest for innovation and investment in new energy technologies. In short, there is neither a natural market appetite nor a short-term business benefit for such technologies. This market gap between supply and demand is often referred to as the 'valley of death' for low carbon energy technologies. Public intervention to support energy innovation is thus both necessary and justified.Public and private energy research budgets in the EU have declined substantially since 1980s. This has led to an accumulated under-investment in energy research capacities and infrastructures. If EU governments were investing today at the same rate as in 1980, the total EU public expenditure for the development of energy technologies would be four times the current level of investment.
The energy innovation process, from initial conception to market penetration, also suffers from unique structural weaknesses. It is characterised by long lead times, often decades, to mass market due to the scale of the investments needed and the technological and regulatory inertia inherent in existing energy systems. New technologies are generally more expensive than those they replace while not providing a better energy service. Therefor a major policy, science and research and planning effort must be introduced.
What is the Commission proposing?
The SET-Plan proposes to deliver the following results: (i) a new joint strategic planning, (ii) a more effective implementation, (iii) an increase in resources, and (iv) a new and reinforced approach to international cooperation.
Joint strategic planning
Joint planning will enable a better orientation of efforts and would be the seed to bring together our researcher and our industry.
Early 2008 the Commission will establish a Steering Group on Strategic Energy Technologies to steer the implementation of the SET-Plan, reinforcing the coherence between national, European and international efforts. The Group, chaired by the Commission, will be composed of high level government representatives from Member States.
In the first half of 2009, to review progress the Commission will organise a European Energy Technology Summit that will bring together all stakeholders in the entire innovation system, from industry to customers, as well as representatives of the European institutions, the financial community and our international partners.
To support the definition of energy technology objectives, as well as to build consensus around the SET-Plan programme, the Commission will establish an open-access information and knowledge management system on energy technologies.
Effective implementation
For effective implementation we need more powerful mechanisms that can leverage the potential of European industry and researchers.
In 2008 the Commission proposes to launch six new European Industrial Initiatives that will target sectors for which working at Community level will add most value – technologies for which the barriers, the scale of the investment and risk involved can be better tackled collectively.
The initiatives are as follows:
- Bioenergy Europe Initiative: focus on 'next generation' biofuels within the context of an overall bioenergy use strategy.
- European Wind Initiative: focus on large turbines and large systems validation and demonstration (relevant to on and off-shore applications).
- Solar Europe Initiative: focus on large-scale demonstration for photovoltaics and concentrated solar power.
- European CO2 capture, transport and storage initiative: focus on the whole system requirements, including efficiency, safety and public acceptance, to prove the viability of zero emission fossil fuel power plants at industrial scale.
- European electricity grid initiative: focus on the development of the smart electricity system, including storage, and on the creation of a European Centre to implement a research programme for the European transmission network.
- Sustainable nuclear fission initiative: focus on the development of Generation-IV technologies.
Several initiatives that are already being implemented, or are well advanced in their preparation, serve as illustrative examples: the European fusion research programme and its flagship 'ITER'; the Single European Sky air traffic management research programme (SESAR); the proposed Joint Technology Initiative on Fuel Cells and Hydrogen; and the proposed 'Clean Sky' Joint Technology Initiative on the environmental impacts of aviation.To bring about a move from today's model of collaborating on projects towards a new paradigm of implementing programmes and to align these programmes with the SET-Plan priorities, the Commission proposes to create a European Energy Research Alliance.
The European Institute of Technology could provide an appropriate vehicle to realise this ambition, through a Knowledge and Innovation Community on energy and climate change.
The Commission proposes to initiate in 2008 an action on European energy infrastructure networks and systems transition planning. It will contribute to optimise and harmonise the development of low carbon integrated energy systems across the EU and its neighbouring countries. It will help the development of tools and models for European level foresight in areas such as smart, bi-directional electricity grids, CO2 transport and storage and hydrogen distribution.
Streamlining resources
Implementation of the SET-Plan will help overcome the fragmentation of the European research and innovation base, leading to a better overall balance between cooperation and competition. Encouraging more focus and coordination between different funding schemes and sources will help to optimise investment.
Two challenges need to be addressed: mobilising additional financial resources, for research and related infrastructures, industrial-scale demonstration and market replication projects; and education and training to deliver the quantity and quality of human resources required to take full advantage of the technology opportunities that the European energy policy will create.
At the end of 2008 the Commission intends to present a Communication on financing low carbon technologies that will address resource needs and sources, examining all potential avenues to leverage private investment, including private equity and venture capital, enhance coordination between funding sources and raise additional funds.
International cooperation
The Commission stresses the need for Europe to take its international cooperation on energy technology to a new dimension. The measures proposed in the SET-Plan (e.g. the Steering Group, European Industrial Initiatives and the European Energy Research Alliance) should bring about a reinforced international cooperation strategy. We also need to ensure that the EU increasingly speaks with one voice in international fora, where appropriate, to achieve a more coherent and stronger partnership effect.
Outline
The following tables from the Technology Map summarise for each technology: the description of the current status and the anticipated developments; the current and future potential share in the European energy demand; the quantified impacts of technology penetration (Environment - Greenhouse gas emissions; Security of supply; and Competitiveness); the barriers to penetration in the European energy market; the needs to realise its potential and the synergies with other technologies and sectors.
Biomass cogeneration, zero emissions power plants:
Biofuels and smart grids:
Nuclear fission, nuclear fusion:
Wind, solar photovoltaics, concentrated solar power:
Solar heating and cooling, large hydropower:
Small hydropower, geothermal, ocean wave power:
Hydrogen and fuel cells:
References:
EU Commission: European Commission proposes a plan to accelerate energy technologies for a low-carbon future - November 22, 2007.
EU Commission, Com(2007) 0723: Towards a low carbon future: European Strategic Energy Technology Plan - November 22, 2007.
EU Commission, DG Energy: European Strategic Energy Technology Plan (SET Plan), website.
EU Commission, DG Energy: Technology map [*.pdf] - A brief and comprehensive description of the current status and prospects of key energy technologies aiming to provide information for the identification of potential European initiatives that could be considered as part of SET-Plan.
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