  It is generally accepted that extreme space weather events tend to be related
to strong flares and fast halo coronal mass ejections CMEs. In the present
paper, we carefully identify the chain of events from the Sun to the Earth
induced by all 12 X-class flares that occurred in 2002. In this small sample,
we find an unusual high rate (58\%) of solar sources with a longitude larger
than 74 degrees. Yet, all 12 X-class flares are associated with at least one
CME. The fast halo CMEs (50\% ) are related to interplanetary CMEs (ICMEs) at
L1 and weak Dst minimum values ($> -51\;$nT); while 5 (41\%) of the 12 X-class
flares are related to solar proton events (SPE). We conclude that: (i) All
twelve analyzed solar events, even those associated with fast halo CMEs
originating from the central disk region, and those ICMEs and SPEs were not
very geo-effective. This unexpected result demonstrates that the suggested
events in the chain (fast halo CME, X-class flares, central disk region, ICME,
SPE) are not infallible proxies for geo-effectiveness. (ii) The low value of
integrated and normalized southward component of the IMF ($B^*_z$) may explain
the low geo-effectiveness for this small sample. In fact, $B^*_z$ is well
correlated to the weak Dst and low auroral electrojet (AE) activity. Hence, the
only space weather impact at Earth in 2002 we can explain is based on $B^*_z$
at L1.
