Impact of Past Climate Changes on Ecosystems and Human Societies

Wed, 19 Nov 2025, 16:00 CEST

Conveners: Erin McClymont & Odile Peyron

Our archives of past changes in climate also include evidence for how physical drivers (e.g. temperature and hydroclimate) impacted ecosystems on land and in the ocean. At the same time, human activities have shaped ecosystems and responded to climate events and climate change. Past changes in climate state and climate variability offers unique opportunities to understand the adaptation and resilience strategies used by past human societies, as well as identifying areas of vulnerability and resilience within natural and managed.

Guest speakers:

• Gustav Strandberg (Swedish Meteorological and Hydrological Institute, Sweden)
• Bronwen Whitney (Northumbria University, UK)

Human land use as a climate forcing during the Holocene

Gustav Strandberg

The European land cover has been affected by human activities for at least 6,000 years. It is therefore highly probable that these land-cover changes were large enough to impact the climate via biophysical effects. By using a novel combination of regional climate models (RCM), dynamical vegetation model and pollen data we can both estimate the difference between reconstructed and potential vegetation (i.e. anthropogenic land-cover changes), and which effects these changes could have had on the local climate. The results suggest that the anthropogenic land-cover changes were large enough to impact climate. This tendency is seen already 6,000 years ago, but becomes more visible with time, as the anthropogenic impact gets stronger. Around 2,500 years ago the land use is more extensive, and so is the effect on climate. These effects do, however, vary with season and across Europe. The results are also model dependent. This is the first time a two-model RCM ensemble is used to simulate parts of the Holocene in Europe. It is also the first time a RCM is combined with novel statistical methods to reconstruct vegetation. This model setup gives an unique opportunity to study the sensitivity of Holocene climate in Europe to vegetation changes (and between models). The high resolution also gives more representative comparisons to proxy data.

Complex societal responses to climate and environmental change in the tropical Americas

Bronwen Whitney

Environmentally deterministic narratives continue to dominate questions of how past societies responded to climate change. Decline or 'collapse' of complex societies have been linked to drought inferred through paleoclimate records. However, correlations between climate and socio-environmental changes do not universally reflect decline or collapse, but instead, may indicate alterations to management strategies as past societies adapted to new environments. Drawing on examples from the seasonal environments of the Bolivian Amazon and Yucatan peninsula, this talk explores diverse management strategies – from control of seasonal flood waters in savanna wetlands to altered agroforestry strategies and promotion of forest resources – in response to changing environmental conditions. The case studies demonstrate that socio-environmental changes were spatially heterogeneous as responses to regional climate change were dependent on local conditions and environments, with different strategies occurring at sites separated by relatively short distances (<50 km). Investigations of past climates and society, therefore, require nuanced interpretation as past people and societies have demonstrated diversity of responses to climate change, which includes resilience and adaptability during times of environmental stress.