Pacific Decadal Oscillation

Parasites
   Animals
   Plants
      Non-Weeds
      Weeds

Pathogens
   Agriculture
      Legumes
      Other
   Other
   Trees

Peatlands

Permafrost
   Degradation
   Impact of Thawing on CO2
   Impact of Thawing on Methane
   Model Inadequacies

Phenolics
   Herbaceous Species
   Woody Species

Phenology

Philosophy

Phosphorus

Phytoplankton
   DMS Production
   Growth Response to CO2
   Temporal Trends

Planetary Albedo

Planets

Plant Hormones

Plants
   C4 Plants
      Biomass
      Photosynthesis
      Water Use Efficiency
   CAM Plants
   Life Span
   Propagation
   Range Expansion

Policy

Pollen

Pollution
   Air Pollution (Non-Ozone)
      Effects on Climate
      Effects on Health
      Effects on Plants
   Water Pollution

Population

Precautionary Principle

Precipitation
   Data Analysis
   Formation
   Model Inadequacies
   Solar Influence (see Letter "S")
   Trends
      Global
      Regional
         Africa
         Arctic
         Asia
         Australia/New Zealand
         Central America
         Europe
            Central
            Mediterranean
            Northern
         North America
            United States
            Canada and Mexico
         Oceans
         South America
         Tropics
   Variability
      Africa
      Asia
      Europe
      Global
      North America

Pressure

Productivity
   Agriculture
   Biosphere
      Asia
         China
            Country-Wide
            Deserts
            Forests
            Grasslands
            Tibetan Plateau
         Other Countries
      Global
         The Distant and Historic Past
         The Recent Past
         The Future
      Hemispheric
      North America
         Central USA
         Eastern USA
         Entire Continent
         High Latitude Regions
         Western USA
   Grasslands
   Oceans

Progressive Nitrogen Limitation Hypothesis

Protein