Identifying the main drivers of the twentieth-century multi-decadal variability in the Atlantic Ocean is crucial for predicting how the Atlantic will evolve in the coming decades and the resulting broad impacts on weather and precipitation patterns around the globe. A paper recently published in Nature from the Met Office Hadley Centre suggested that aerosols are a prime driver of twentieth-century North Atlantic climate variability, based on simulations using the HadGEM2-ES (UK Met Office Hadley Centre Earth System Model).
Read More…
This collaboration, led by NOAA and EPA scientists and entraining expertise from the University of Connecticut, evaluated the potential effects of climate change on cusk (Brosme brosme) in the Northwest Atlantic. Numbers of this demersal (bottom-dwelling) fish (Fig. 1) on the Northeast Atlantic continental shelf have declined dramatically over the past several decades. This is believed to be primarily a result of fishing activities. However, changes in the distribution and abundance of a number of marine fish stocks in the Northwest Atlantic have been linked to climate variability and change, suggesting that both fishing and climate may affect the future status of cusk. Read More…
Our capability to observe ocean changes has improved dramatically over the past two decades, motivating interest in how these observations can be used to constrain climate change simulations. Projections of future surface climate change and ocean circulation change are both very uncertain. This research shows that circulation changes are important to the surface climate change and we describe a mechanism for the connection. Read More…
Dust is one of the most abundant aerosols in the atmosphere, and by scattering and absorbing solar radiation, it affects climate. Anthropogenic dust is largely ignored in most current climate studies. We show how pervasive it is throughout the world, and that it is mostly associated with croplands.
Read More…
Dust is one of the most abundant aerosols in the atmosphere, and by scattering and absorbing solar radiation, it affects climate. In particular, anthropogenic dust is a significant source of radiative forcing on the climate system. Increasing numerical resolution of climate models provides an opportunity to create a realistic, high-resolution dust-source inventory. Read More…
The future response of Atlantic meridional overturning circulation (AMOC) to increased carbon dioxide is known to be uncertain, with models showing 21st century weakening of 0 to 50%, according to the IPCC 4th report.
The authors examined the high northern latitude heat budgets of closely related climate models having large and small responses of AMOC to increased carbon dioxide. This paper shows that AMOC weakening is associated with the response of other important climate variables, so its uncertainty affects the projections for those variables as well. Read More…
Clouds and water vapor are among the difficult features of the atmosphere for global climate models to simulate because they are affected by physical processes that operate over very small areas compared to the weather patterns that the models explicitly calculate. The authors used satellite data to assess the representation of clouds and water vapor simulated by several climate models that will participate in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Read More…
To combat global warming, there have been suggestions to increase the albedo of (i.e. brighten) low-level marine clouds by deliberately injecting them with aerosols. Though such cloud seeding could mitigate global-mean temperature rise through the aerosol indirect effects, the full climate response to this geoengineering scheme is poorly understood. For example, one prior simulation of cloud seeding exhibited catastrophic rainfall decrease over the Amazon, while another showed moderate rainfall increase there. Read More…
Using two fully coupled ocean-atmosphere GFDL models, CM2.1 and CM2.5 (a new high-resolution climate model based on CM2.1), the characteristics and sources of SST and precipitation biases associated with the Atlantic ITCZ were investigated and compared. Read More…
