On page 2 of the report is the following statement:

Observational evidence from all continents and most oceans shows that many natural systems are being
affected by regional climate changes, particularly temperature increases. {1.2}

Below this point, beginning at the top of page 3, the report makes the following statement:

Of the more than 29,000 observational data series, from 75 studies, that show significant change in many physical
and biological systems, more than 89% are consistent with the direction of change expected as a response to
warming (Figure SPM.2). However, there is a notable lack of geographic balance in data and literature on observed
changes, with marked scarcity in developing countries. {1.3}

Figure SPM.2 is then introduced.

In reading the caption for Figure SPM.2, I found that the 29,000 data series referenced in the above statement are a subset of a total of 80,000 data series which have met 3 criteria. I can understand the reasoning for the first two criteria but the third criteria escapes me. It states that data series which did not display a significant change in either direction were excluded from the analysis. My question is why were they excluded?

It seems as though the figure and the attendent statement are meant to establish the high correlation between the expected change in the variable measured and global surface warming. If this is the case, why were data series with no significant trend excluded since that would have a direct bearing on whether such a correlation exists?

I went back to the WG1 Technical Report and the WG1 Summary for Policymakers to see if there was any explanation on this, but I couldn’t find this figure or its corresponding statement in those reports.

Does anyone know why this figure was included in the Synthesis Report when it wasn’t displayed before?

Does anyone know why the third criteria was introduced?

On page 2 of the report is the following statement:

Observational evidence from all continents and most oceans shows that many natural systems are being
affected by regional climate changes, particularly temperature increases. {1.2}

Below this point, beginning at the top of page 3, the report makes the following statement:

Of the more than 29,000 observational data series, from 75 studies, that show significant change in many physical
and biological systems, more than 89% are consistent with the direction of change expected as a response to
warming (Figure SPM.2). However, there is a notable lack of geographic balance in data and literature on observed
changes, with marked scarcity in developing countries. {1.3}

Figure SPM.2 is then introduced.

In reading the caption for Figure SPM.2, I found that the 29,000 data series referenced in the above statement are a subset of a total of 80,000 data series which have met 3 criteria. I can understand the reasoning for the first two criteria but the third criteria escapes me. It states that data series which did not display a significant change in either direction were excluded from the analysis. My question is why were they excluded?

It seems as though the figure and the attendent statement are meant to establish the high correlation between the expected change in the variable measured and global surface warming. If this is the case, why were data series with no significant trend excluded since that would have a direct bearing on whether such a correlation exists?

I went back to the WG1 Technical Report and the WG1 Summary for Policymakers to see if there was any explanation on this, but I couldn’t find this figure or its corresponding statement in those reports.

Does anyone know why this figure was included in the Synthesis Report when it wasn’t displayed before?

Does anyone know why the third criteria was introduced?