Calculate, map and used of critical loads and exceedances for acidity and nitrogen in Europe Professor Harald Sverdrup Chemical Engineering, Lund University, Sweden

The European game plan

An effect-based methodology

Defining the critical load The maximum amount of pollution into an ecosystem that does not cause significant damage to system resources, survival, structure or function

The critical load Contributions to acidity in the system Contributions to neutralization in the system

Targets to protect

Response was measured Norway spruce: BC/Al=1.2 Scots pine: BC/Al=1.0 Birch: BC/Al= 0.8 Beech, Oak: BC/Al==0.6

Many effect parameters are available

Models available for critical loads for acidity and nitrogen Empirical models –Skokloster model –Empirical nitrogen critical loads Simplified models –Simple mass balance (SMB) –F-factor models (lakes) Integrated steady state models –PROFILE model Integrated dynamic models –VSD model (soils) –MAGIC model family (lakes) –SAFE/ForSAFE-VEG model family (terrestial ecosystems)

The order of the actions Static approach first - Simple mass balance models - Complex approach; PROFILE - Create critical loads maps Apply dynamic models at sites with enough data - Single sites - qualitative assessments - Generate regional approach - representative information capture and transformation

PROFILE/ForSAFE

Revised critical loads for forests, lakes and streams

Critical Load for acidity and nitrogen in the grid system

Critical loads for ecosystems in Europe, forests, open land and lakes

The best solution is sought for

The Swedish example 1988 exceedence was far too much !

Medel: 37 mekv/m2/år Exceedance depend on the receptor chosen

Exceedance with the Göteborg protocol

Sulfur deposition Green = 3-6 kg S/ha yr Red > 25 kg S/ha yr

Exceedance of critical loads Blue < 3 kg S/ha yr Red > 25 kg S/ha yr

Validation is difficult

Exceedance and effects are NOT simultaneous in time

13 NFCs submitted Dynamic Modelling outputs: Austria, Bulgaria, Switzerland, Czech Republic, Germany, France, Great Britain, Ireland, Italy, Norway, Luxembourg, Poland, Sweden. Countries now into integrated regional dynamic modelling

What are the model predictions? Recovery does not reverse the path of acidification Fast effect initially, very slow final recovery Recovery is not 100%

Prediction: Lake pH in Scandinavia

Dynamic simulations: Soil pH in the long run in Sweden

But BC/Al what we work with

Soil base saturation, lost ?

Simple messages to policy? Critical load (CL) –No significant harmful effects if deposition don’t exceed CL Target load (TL) –Recovery by specified year if deposition don’t exceed TL

Interpretation of target loads Will not recover by 2030 Will recover by 2030

TL max (S) th percentile CL max (S)

20 years with critical loads 1968 Acidification put on the official agenda by Prof Svante Oden in Uppsala 1979 Convention on long range transboundary air pollution 1985 First Olso protocol on flat rate 30% sulfur emission reduction 1990 The second Oslo protocol, effects based but settling on 60% sulfur emission reduction 1999 The Göteborg protocol, effects based settling for -85% S/-30% NOx 2010 revision of the Göteborg effects based protocol

Conclusions International efforts to prevent acidification have been very successful Critical oads very extremely successful in linking environmental goals through science to policy Acidification remains as a large and significant problem in large areas of Europe

Time for questions !!

Discusssion slide

Hva skulle ha hendt om vi ikke hade hatt noen internasjonale avtaler og nedfall som i 1980 for all fremtid ? Gissa ! Do nothin’ and keep acid rain for good ?

Base saturation melts like butter in the sun