1.1 A world divided in energy 9
tight oil sites may have EROI ratios lower than 5. This is a huge shift from the
traditional oil wells where the EROI ratios could exceed 100. From the EROI
analyses and forecasts from energy agencies a picture is emerging. The traditional
resources might still be plentiful, but the expected rates of production
may become a limiting factor. As established earlier, the world's energy demand
is increasing and for this reason alone it is vital that the renewable resources are
exploited to a much larger degree than they currently are. The second major
driver for increasing energy production from renewables is the environmental
impact of burning fossil fuels, which have lead to unprecedented high levels of
CO2 in the atmosphere. The climate change discussion has a lot of momentum
these years and there are numerous reports predicting the consequences of the
ever increasing CO2 emissions 2225. Although the full eect of the emissions
is impossible to predict with our current knowledge, it is certainly a risky experiment
we are carrying out on "laboratory earth". An interesting example
from the International Energy Agency, IEA, is shown in gure 1.10, where the
global CO2 emissions from the energy sector are plotted together with an evaluation
of a so called global carbon budget. The background for this model is a
scenario which takes into account recent pledges from dominant countries and
the carbon budget is evaluated as the amount of CO2 we can emit while only
raising the global temperature with 2 oC by 2050 26. According to that model
we will have spent the budget in 2040 where the emissions of CO2 are not even
expected to peak.
Figure 1.10: CO2 emissions in Gt in the period 1890 to 2040, shown as bars and
on the left axis. The blue line and the right side axis represents remaining global
carbon budget from a scenario based on recent pledges from the worlds policy makers.
Numbers from 2014 are predictions. Figure from 26.