Increasing forest harvest, e.g. to increase bioenergy or material substitution, all else equal, means a smaller land sink. But, a land sink is needed to help reach net zero (may not be possible to get all emissions to exactly zero).
3. The forest sink is mainly from forests remaining forests, so carbon uptake comes from management or environmental factors (CO₂ fertilisation, climate change).
Afforestation can be increased & emissions from other land use types & transitions can be decreased.
Based on the new NGFS scenarios, up to a 60% drop in fossil CO₂ emissions by 2030. This includes a pathways with divergent polices (Divergent Net Zero).
(Different colours, different IAM).
EU & US reach net zero around 2040-2060, depending on model and scenario.
For the lingo, "Net Zero 2050" is an orderly transition to 1.5°C & "Divergent Net Zero" is a disorderly transition to 1.5°C, implying policies are implemented immediately, but not uniformly.
Don't ask about India...
[Technically, I guess the rebound in MESSAGE is since carbon prices stop growing (& decline) after net zero, which allows India to emit more. That would be my hypothesis... Is this rebound believable?]
There is no physical transfer of electricity, just a digital transaction with some $.
A GoO is basically a certificate to say that some renewable electricity was produced, & the certificate is then sold onward to an entity. The entity then claims they are using renewable electricity, even if they are connected only to a coal power plant.
The average consumer that is physically using the renewable electricity generally has no idea about this virtual transaction. So, Norwegian's think they are using Norwegian hydropower & German's think they are using Norwegian hydropower. I guess no one is using the coal then?
The EU has a LULUCF sink of ~250MtCO₂/yr:
* ~300MtCO₂/yr is forests remaining forests (a share of which is due to climate change & CO₂ fertilisation)
* ~50MtCO₂/yr is land converted to forests
* ~50MtCO₂/yr is increased storage in wood products
* The rest is a source
This sink has a huge policy significance, as the sink allows to offset emissions in hard-to-mitigate sectors & reach net zero in 2050.
But, using forests could also help reach net-zero by displacing some fossil fuels?
Just focusing on forests, the EU could increase harvest, weakening the sink, & use the harvest to displace materials (e.g. cement in construction) or fossil fuels (e.g., bioenergy).
Current policies may take the world to ~3.2°C (10-90% range 2.3-4.4°C due to climate uncertainties), which is much less than >5°C in SSP5-85.
The bold lines are from the NGFS scenarios used by financial institutions for 'stress testing', the thin lines are from IPCC SR15.
Another organisation that has been doing work on 'where we are heading' is the @climateactiontr, which has quite consistent numbers as the NGFS (though quite different methods).
* NGFS is based on modelling
* CAT is more a statistical approach
Global CO₂ emissions grew at 2.6%/yr in the 2000s, but this dropped to 1.0%/yr in the 2010s.
Can we see this in the atmosphere?
If emissions growth continued at 2.6%/yr in the 2010s, it would lead to ~0.3ppm difference in 2019, or cumulatively 1.3ppm over the 2010s.
How did I do this? 1. Assume emissions continued at 2.6%/yr from 2010 2. Get difference with current emissions 3. Multiply by airbourne fraction (AF, estimated 1960-2010, 0.43) to estimate atmospheric increase 4. Convert to ppm (1ppm = 2.124GtC, GtCO2 = 3.664 GtC).
We should see this in the atmosphere, but how confidently given variability?
The effective difference in growth rates is ~2%, which we should be able to detect after 5-10 years. Though, note in the commentary, we compared 1% & -1%, not 2.5% & 1%. rdcu.be/buifD
"It is not obvious that the cheapest resources with the lowest carbon footprint lie in the resources already discovered... To stop exploration at this time would cause a major threat to the world's energy security", are the arguments from the Norwegian Oil & Gas lobby
"Recent polls have shown that 60% to 70% of voters continue to support future Norwegian oil & gas production"
[Perhaps the political niche is threading the needle between investment for old & new fields, taking the IEA's lead]
THREAD: Bioenergy use in the @IEA Net Zero 2050 scenario
I have seen a few comments that the IEA uses loads of bioenergy. Let's have a look...
First up, overall, bioenergy use is lower than in equivalent scenarios assessed by the IPCC, particularly in 2050.
2. An important detail is that the IEA assumes traditional biomass is gone by 2030. Traditional bioenergy "is unsustainable, inefficient & polluting, & was linked to 2.5 million premature deaths in 2020"
The IPCC only has a slow drop, so the IEA must build up modern bioenergy.
3. In terms of modern bioenergy, the IEA has similar levels as the IPCC up until 2050.
* Rapid growth to 2030 is to compensate traditional bioenergy
* Slowdown to 2050 is to limit to 100EJ per year, view by many as sustainable.
There is a lot of confusion about net-zero GHG & CO₂ emissions, they are different.
The EU & US have a target of net-zero GHG emissions in 2050, which is ~20 years ahead of the global average (coincidentally, global net-zero CO₂ emissions is ~2050).
For developing countries to have a later net-zero GHG year, say 2090 (~20 years after the global average), it requires that developed countries are net negative to compensate developing countries & maintain net-zero GHG globally. (a point often made by @Oliver_Geden).
I think we all agree & accept developing countries will find their own path to net-zero, & one that is later than developed countries.
But, I also think many confuse the net-zero years for CO₂ & GHG emissions.
Many obsess on 2050, when there is actually a broad range!
Mitigation will cause the ocean sink to have reduced efficiency because of:
* reductions in carbonate buffer capacity in scenarios with intermediate or no mitigation
* reduced transport of anthropogenic carbon from surface to depth in 1.5°C scenarios.